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57LFC/AN

1. 15I 584 NOTES UNLESS OTHERWISE SPECIFIED Q7 BEG MMBT3904 1 ALL RESISTANCES ARE IN OHMS R6 10 0 15 100 R53 5 3 8 R36 pro P R12 D mu mu D MJE15029 Q14 HEATSINK MMBT3906 IGND 15I DISTORTION LOOP ERROR AMPLIFIER 07 3 MC34081 3227 6 GM 27MA V 242MA V MID CURRENT OUT ISOLATION BARRIER s m t nd xe D L 2 MID CURR ENABLE 4D5 IDAC SW 51 ERROR OUT R27 4 TP6 ciio 10 0K AQV225 0 00390 ACDC SW R102 151 R2 10 0K R186 10 0K 22M U13 TP7 10 015 MC34081 2 MMBT3904 14 xiu wl MJE15028 ogo 2 48 3 289 HEATSINK 5237 1512 7 5 IGND 5 sav 41512 8 4 TA B 4 s 2 gis 7151 R32 96 R51 1213 MMBT3906 13 0K C HICURRENT 1512 0 004791 1 2680 1 00K C38 7 K5 LOCURR_RTN T 330P R45 8 Sub ois CR15 MMBD1503 SHUNT SEL3 MID CURR RTN GMe214UA V MMBT3906 1 6 lt 4 6 gt 3C8 lt gt SHUNT_SEL2 gt
2. lt 19 1 gt 555 d 11 T10 10 rar T20 U20 R10 R20 R2I LT1781 D 1 1 V cee vec 5 et 82 0 10 CALSW P n ND TO SERIAL PORT vec ul v n T10 14 REFERENCE DESIGNATON T2I T20 LAST 019 USED NOT USED 12 4 R10 13 304 R20 R21 c73 10 14 LT1781 Ell 1 3 WC N 1 v L 6 J3 1 ci L2 5 124 C24 1 72 o Vs 5 IUE MP5 MP1 2 i 0 1UF 12V 0 P2 U7 5 m vec GND R60 R10 12 16 23 33 35 4 2 1805324283 AUX SERIAL PORT R36 38 53 IRQ lt 5 gt NCISEO4 3 5 555 Gss 4 S2 51 Halalan vec U35 U12 13 15 18 22 23 mie m m OOM y U26 31 A A 4 MMIII OOO 1 Fm qd Hl K m g a O H BAMA AA O x x Blau 255 VIN 22 R59 dodo Aes gu d 22 3 5 412 GOHA 129 875 vo GND Was 21 2980 5 67 TRST PB7 IRQ vee TO MOTHERBOARD TCK IACK ES TMS TACK TDI TACK 1270 MC68306 AMODE TRO4 A19 IRO7 mis 9 222 15 ENCSIG 217 LWA
3. 5V NY REF DES PARTNAME HSNK P5V cu U3 138 HC 16 197 04 14 4 U5 U6 U8 U9 UCN5800 07 74HC374 3 V PANEL LED S 374 HC IQ DATA T 0 REJ 2 VOLTREG3P DUAL HSNK D 2 00K 1 R16 ri EN RE ILL U OBFIAuLunlln ld ellnlI Illl iu ie ha ane EO a hs P R15 r WARNING 2 00K OPERATE STANDBY TG DATA CKIT C110 m CLIN A IG CKHVCUR 49 9 5124 i R99 IG DATAI 5RLH 1 100 DATAO 86 6 CLIN B R 5V c20 AAA 0 1U 49 9 C8 0 1U 57 45V 1 5V R106 74HC138 10 1 ANN 1 6 9 1 00K 412VG C122 6 i 0 1U 5 4 1 Ei 4 3 12 L C113 C112 IN Our 4 70 0 10 1 1 1129 2 lt UONSSUDE 16 15 DS2E1 16 DS2E1 R125 1 86 6 R97 U26 CLOUT 1 T T AAA T 15MIL CLOUT B 200 AA LT1223 E cre 1 6 9 T BAV74 T 100P 2 OTT 1 100 1 4 1 ai 15M R9 0 3 12 R101 74HCU04 IN OUT 3992 49 9 1 00K l U28 14 Ciis 5 6 2 0 1U d H STB UCN5800L CLR DRVR H 12VG 1 RLY RST pov K6 1 C21 0 1U J1 T DS 2 SER CLK A 2 F DS 3 SER CLK B UCN5800L DS2E1 DS4E 6 7 8
4. 15 t DUAL ASSY T IN OUT mess 1329 15V CR67 mE C105 4 OUT 0 10 100MIL 1015 Gai D 100V R14 e CR29 20V 15AC2 3300U 0 1U MBRS140 GF1G 5 on 35V 1 5SMC20A TP24 TP25 C104 0 19 1233 100MIL 1359 SCOM VR15 15COM C94 C82 L c76 20V 33000 0 1U TO220HS 100 5 35V 1 5SMC20A TP43 TP26 15UNR 15 6TURN 100MIL lt X331 CR31 GF1G 15V GF1G CR19 CR18 uev MBRS140 MBRS140 TP10 L2 M 5RLH 6TURN 100MIL 5AC2 50 odd CR24 C34 2 7 200 cL uc 4 TO220HS T 1000 10 10 51 16V 1333 5V KBPoaM LP39 11 2398 SUNR L3 m 55 CET L Mind R52 6TURN 100MIL 200 L R67 200 2 CR25 C35 2 7 15000U 2 00K R51 n 100U MBRS140 9 10 ney 604 TO220HS 16 TP8 100MIL 1361 207 5COM 1 M DCOM C69 R66 CR23 2200U TO220HS 0 1U 100 0 19 25V 2 00K 25V TP35 TP9 5UNR 5v E non pene TP3 FAULT R108 5 R20 10 0K c gt 100 0 10 15V BAT54A Fi 3 U10 5V 15V B 1 R31 2 2 9 12 13 NS VR16 V 5245
5. 5V 5V C83 0 1U R133 DAC CS lt 1 gt PORTU 499 sps AD MUX 7 0 OFF EN lt 7 0 gt 128 BA6 8C3 1094 gt c 9 SRC Erel PROG mE 5V AD CS SCALER OUT 11 0 DCLK 5D3 8B2 887 1C8 45V 2 lt 0 ___ EXT CLK 55 3 QUI 3 C141 4 ses OUT RELAY WR lt 0 gt DDS IN 0 1U 5 122 FOR 012 85 C86 C87 C89 C90 C96 c99 C104 5 RX 2 V 0 1U 0 10 0 1U 0 1U 0 1U 0 1U 0 10 0 10 2 5 9 DATAO PRI CHANGED io Sone DONE psa BYPASSES FOR U5 NCONFIG 45V 7 P 8B3 8B7 ERR R116 NSTATUS V 8B7 ANN OUD 851 34 2K 5 ps2 ae RED E 2D6 WTADDR lt 18 0 gt gt Ul o c 7C4098 WTDATA 15 0 15 1 5 2 a 100 7 SEC XING STROBE 6 3 a2 101 13 4 jas 3 Fo fay lo sees ho ise 17 103 e s MAYA IIIS ele e e ojojoj 16 NIN jx js jo jx x espe ex ju e e eje ISI aaa 2 LLI 11
6. IG 5 lt 7 0 gt 10 10 ddd P206 S 0008000000000000000 90 DATAO 2 BUS 5 lt 7 0 gt 5 1 H 5 Hd H DCLK TCK CONF DONE TDI 45V 20 GNDINT 1 0175 1 0174 1 06 1 0173 1 07 1 0172 8A6 1 08 1 0171 OUT CONE DONE 1 99 VCCINT 8D3 GNDINT 1 0169 RAM CLKUSR 1 0168 1 012 1 0167 1 013 1 0166 1 014 GNDINT 1 OUT SEC STROBE VCCINT 1 0163 BAG 8B7 rote 1 9162 856 LIND 1 019 VCCINT RD PRI STROBE NP 1 IG WR 20 WR pea GNDINT 1 0157 1 3 mE RDY BSY 1 0156 L 286 1 024 GNDINT Pede 5 gt 1 025 1 0154 1B3 our INIT DONE 1 0153 HF LF A12 VCCINT 05 1 0152 lt I o28 I O151 AD MESS 6 1 029 EPF10K30RC240 VCCINT TC MEAS 508 eps sas COUT 1 030 1 0149 ISO MEAS 1 031 1 0148 GNDINT 1 0147 8C2 503 OUT IG WR 1 033 1 0146 1 034 GNDINT 5B5 SHORT 1 035 I O144 1 036 1 014
7. n zs 22 825 4 ASSEMBLY 10 08 86 Vraa ga Citt 6 T H1 H4 RIVETS 4X 57LFC 4008 apv057f eps Figure 5 7 A8 High Voltage PCA 5 54 List of Replaceable Parts 5 Parts Lists Table 5 8 A9 Out Guard CPU PCA Description Number Qty BATTERY PRIMARY LITHIUM MNO2 3 0V 0 560AH CR2450 COIN PC 821439 cn 24X5MM BULK 2 CAPACITOR SMR CAP CER 22PF CAPACITOR SMR CAP CER 22PF 10 50V C0G 1206 50V C0G 1206 740563 2 CAPACITOR SMR CAP CER 22PF 1096 50V CO0G 1206 740563 2 CAPACITOR SMR CAP CER 0 01UF 10 50V X7R 0603 644838 CAPACITOR SMR CAP CER 0 1UF 10 25V X7R 1206 747287 KCN CAPACITOR SMR CAP CER 100PF 10 50V COG 1206 CAPACITOR SMR CAP TA 47UF 20 16
8. RAM BANK 1 128K X 8 RAM X 4 RAM BANK O0 lt 19 1 gt 5 vec I x I P D 9 12 3 NC7SZ04 g 8 vee 8 10 14 9 14 9 A2 DOL 2 25 104 c29 10 8 AA 17 17 13 7 18 12 18 1271 5122 U33 DQ4H8 327 0 01U 034 04 3as 2 zo 2 20 29 44 27 A8 MsM51008 07 21 wA M5M51008 DQ7 21 A9 23 10 011 25 11 5 TRE 13 E28F004BL 111214 A15 2 16 010 RESET PAGEL 258 269 27 10 28 11 32 12 33 13 34 14 35 15 CEL N 24 CE2 OE 29 we i2 5 p 18 REAL TIME CLOCK 5 lt 3 gt RTC64613 12 8 lao R60 2 7 Ja 3K 5 A U32 M5M51008 U35 M5M51008 20 9621 E28F004BL gt lt 8 lt 0 gt y TAT 1A4 1 C42 Tes 1 C36 1 C19 1 25 1 1 1 C37 1 1 C11 1 cis 0 01U 0 01U 0 01U pa 0 01U i 0 01U i 0 01U i 0 01U i 0 01U I 0 01U I 0 01U 0 01U I 0 01U C20 0 01U vec C50 C51 1 52 C27 45 1 C26 1 2 1 C44 1 C49 1 C53 1 C12 1 C16 1 C21 10U 10U 109
9. 862 R61 8 Fa N CAUTION SUBJECT TO DAMAGE BY STATIC ELECTRICITY CA Aves CR10 95 15 00658865 9 H4 RIVETS 4X 93 1 CR13 04 H vaadp Ga CRO R43 R44 R45 Figure 6 3 AS Ohms PCA 6 11 57LFC Service Manual 6 4 V NOTES UNLESS OTHERWISE SPECIFIED 1 ALL RESISTANCES ARE IN OHMS 2 ALL CAPACITANCES ARE IN FARADS 3 ALL RELAYS ARE SHOWN IN THE RESET POSITION COMP EXT HI BUFHCOMPV HI OHMS HI HI SNS HI OHMS OUT HI OHMS SNS HI
10. 4 3 Replacing the esae reete ee aee eene dd 4 3 Cleaning the Air 0 4 4 Replacing 4 6 Cleaning th Exterior iecit ee re rere Gan List of Replaceable Parts Introduction cte ee tert t v deti ecce UR E vet dg 5 3 How to Obtain Palguu ul l ii eene eene nennen 2 3 Service uuu 2 4 ou Schematic Diagrams J iii 57LFC AN Service Manual List of Tables Table Title Wd S HLEC Pe 1 4 2 1 Functional Description of Motherboard PCA Relays 2 6 2 2 Motherboard PCA Power up and Fault Relay States 2 3 Motherboard Final Relay States by Instrument State 2 4 Control Register States by Instrument 51 2 5 Functional Description of LED 2 6 Motherboard PCA Test Points 2 7 Functional Description of A5 Ohms 2 8 5 Ohms Power up and Fault Relay States
11. 98 a Been ma j o Note Calibrated ohm values are measured and stored during calibration These values can be accessed remotely or from the factory test report supplied with the instrument This measurement assumes four wire connection The measured value is made with a Fluke 8508A or equivalent Calibration and Verification Verification Tests FLUKE 57LFC 57 FC 5 5 8508A FLUKE extric sawpLe 008 Figure 3 5 8508A Connections to the 57LFC for 2 Wire Compensated Ohms Table 3 6 2 Wire Ohm Values Done a o a ua u ua a j S ma 8 57LFC AN Service Manual DC Current Test The dc current amplitude accuracy test verifies the accuracy of dc current at the Calibrator output terminals First use the 5720 to characterize all the points in Table 3 7 Next connect the 8508 to the appropriate terminals on the Calibrator as shown in Figure 3 6 and verify the Calibrator is within the limits shown in Table 3 7
12. 16 OX L 8 8 8 8 91109 OM L 515 1 5 8 8 8 915 061 1 1 1 1 1 1991984151505 Mz 061 o p z 5 1 5 1 58 8 8 8 5 AALS 001 o pee 2 2 2 24 4 4 S 1 S S S 8 1 8 5 91109 001 5 5 1 85 8 85 8 1 duioo Mz U 61 1 1 1 8 8 5 91109 61 o 5 5 1 8 1 8 5 8 1 8 A81S 2 O 01 o 1 1 S 8 5 5 5 5 5 91109 MZ 501 S 5 1 5 1 12 S 1 S S S S SS ss s A8LS 9 MZ 5611 Ovi 1 a 8 5 5 duio MZ 561 5 2 815 O 1 a 11 8 1 S S 9109 51 1 5 11 1 5 1 8 8 8 8 AGLS dao uous 11217 8 2 8 V 91816 SUI 8 6 6
13. THERMISTOR THERMISTOR DISC 0 18 25C 875273 E RT7 12 RT6 THERMISTOR PTC 0 02 30V 2W 3A HOLD 6A TRIPRADIALBULK PTC 0 02 30V 2W 3A HOLD 6A TRIP RADIAL BULK 2075107 RV1 5 VARISTOR 22V 20 1 0MA 500777 5 TP7 14 CONNECTOR TERMINAL TEST POINT 1510 TAPE 602125 i AMP AD744J 4 5 TO 18V 2MV OFFSET 6MHZ HI SLEW 629992 ss 508 IC CMOS Eu ae aua 8 LINE DCDR W ENABLE SOIC 783019 1 IGCMOSHEXINVERTERUNBUFFEREDSOC 000 CMOS HEX INVERTER UNBUFFERED SOIC 806893 05 6 U8 9 IC BIMOS 4 CHNL DRVR W LTCH SOIC 929781 Cmm 29 IC CMOS OCTAL D F F EDG TRG SOIC CMOS OCTAL D F F EDG TRG SOIC 866798 EN IC COMPARATOR CUT lt lt 14 PIN SOIC 741561 EN u11 u18 U18 DUALOPAMP OP AMP 1756700 x U23 IC COMPARATOR DUAL LOW PWR SOIC 837211 E ui HEATSINK ASSEMBLY ASSEMBLY 2114956 1 we 57LFC AN Service Manual Table 5 3 A3 Motherboard PCA cont Ref Part Des Description Number Qty U27 IC ANALOG SWITCH DG444 12 20 85 688457 1 OHMS SPST QUAD NC LOW LEAKAGE SO16 TAPE IC TEMP SENSOR LM35D 4 30V 2C 10MV C TO 92 BULK 2111629 HEATSINK ASSEMBLY WITH 2 MJE15028 XSTRS 2065328 HEATSINK ASSEMBLY WITH 2 MJE15029 XSTRS 2065337 U33 34 HEATSINK ASSEMBLY 2114974 VR1 2 ZENER UNCOMP 56V 5 2 2MA 0 4W 832568 mL ZENER COMP 6 4V 296 20PPM 1MA 419036 VR4 5 ZENER UNCOMP MMBZ5245B 15V 5 8
14. fed jg So R85 R87 189 4 ASSE CAUTION SUBJECT TO DAMAGE BY STATIC ELECTRICITY p83 E6 as 10 0 cia R79 R80 na2 E S cem E dal 5 cis 5 Orn com VR33 R177 ce DN Ser 223 fees R22 82298230 8231 R218 8270 221 CR56 CR57 E 4 MP14 R224 Rez Reed 6 32 Figure 6 6 A8 High Voltage PCA 57LFC 7608 Schematic Diagrams 1 TP9 NOTES 1 ALL RESISTANCES ARE IN OHMS 2 ALL CAPACITANCES ARE IN FARADS 3 ALL RELAYS ARE SHOWN IN THE RESET POSITION CR31 BAV199 UNLESS OTHERWISE SPECIFIED 15V CR32 199 059 MMBT3904 15V 45V 150 2N5401 CR14 GF1M 13 3K B gt 15 as 5254 E 15V 842 ML M U5 How N OPA637AU 8 220VIN 2 55 P108 288 MMBT3906 CLA Va 3 4 A 6 22VIN AA re TPS 17 2 2K
15. fe e sm fe seem o es wee omo Calibration and Verification 3 Verification Tests Current Output Compliance Test Connect the Calibrator to the 8508A as shown in Figure 3 8 Apply the load to the 8508A terminals For safety reasons please observe the power limits of the resistors used in the test See Table 3 9 for power limits e Apply the maximum dc current output 1 8 Q load for 4 V compliance voltage when set to 2 19 A dc Verify that the current remains at the correct limit by measuring the current as described in the resistance accuracy test earlier in this Chapter FLUKE 57LFC WEISE 57i Fc system cauienaron 8508A FLUKE 85084 55 5 e on 9 ioca 9 6 ame apv011f eps Figure 3 8 8508A Connections to the 57LFC for Load Current Compliance Test Table 3 9 Current Output Compliance Limits Voltage Output Compliance Test A A Warning This instrument is capable of outputting lethal voltages Observe all safety precautions while performing this test Connect the Calibrator to the 8508A as shown in Figure 3 9 Apply the load to the 8508A terminals For safety reasons please observe the power limits of the resistors used in the test Table 3 10 contains the test limits Apply the max
16. 001 qv pp ilsi si2g s 2 2 s 2g si si si si si si s 2J s 2J si si si si s 2 s 2J si si si si s x A amp LS Mz Oy 6L 274 el ae see duioS Mz Oy 61 8 8 8 c v 8 8 91215 SUI 8 8 101816 9 vM EA M M A LL 6 S 0 L 0 6 419 x 8 9 S 2 13 22 17 17 97 enya 2 24 2 A5 Ohms PCA Theory of Operation 061 01 AJUO OML p pejoejes se asuas jeuJeju sesn pue esueg ejouleH sesn AIM sen e A THO ay esn ON pue 4104 15 195 OSM pue 62 SZA AALS Uonisod u q 19470 19501 OEY pue 62 eoueijsisaJ e uayM 910 195 5 19591 J x Table 2 9 Final R
17. 0 IG FAULT eos REG _WR lt 2 gt 4 HI NPCLK om 2 1ce OUT 1 3 5 5V vj 4 cj 2 U71 _ MAX705 IY E 4 WDI R130 R93 4 prr WDO 8 2K 2K 7 3 9 7 PFO 5 5 0 1 RELAY WR lt 1 gt 10 0MHZ RESETD WD RESET 355 IG 8 lt 7 0 gt aci A BATS4A ae DDS_SYNC_OUT 8 INT CLK 57LFC 1006 exp 2 om NP lt O gt INT 3 AD MUX 7 0 REG WR lt 1 gt 7 5 8 806 8C3 6 8 of 8 DDS CLK IN Dyp yD DONE IN 503 LS RD DDS CLK OUT iT 188 108 7 6 8D3 CR10 INT CLK BATS4A 3A6 PRI XING STROBE 2 Figure 6 4 A6 Digital Synthesis cont 6 25 57LFC Service Manual TZ2C3 e c58 i 21690 18166 oo R1T2 7 18197 gt R103 4 B ez E usc D RIL7C COR120 00 1 8 R100 05 c22 m 30 21 0 c20 1507 1407 p OE oci 29 E33 4
18. Detailed Description of the 220 V Amplifier Detailed Hardware Description of the High Voltage Regulator Heat Sink Temperature Digital Interface and Out G ard CPU ince teet qe teinte Real Time Clock IBEE 488 Intetlace s tere 2 52 SU s OMEN OOV 3 4 Instruction Step INS L3 4 Reference Step 3 4 pj mc 3 4 MEC Test EA Calibrator Configuration and Pre check DC Voltage 3 7 Voltage dI icm 3 9 AC Voltage Accuracy Contents continued Frequency Accuracy Testos rnn e DER E DC Current AC Current Best Current Output Compliance Voltage Output Compliance Test sess Harmonic Test Levels for AC Volts Harmonic AC Current Test External Verification Test Check Malte MANIC Cie sca CER ERO EXPRESS
19. Guard Compensation Circuits M M aaa Digital Synthesis PCA Precision Dual Tracking 7 V References Precision 28bit PWM Dual DC Voltage DDS Waveform Generation AC Voltage DG Current Operat On eet AC Current u Thermocouple Temperature Measurement Iso thermal Block Reference Junction Temperature Measurement Thermocouple Voltage Measurement Thermocouple Temperature Simulation Analog to Digital Converter Fault Detectlioh et ed ee ORE Digital Control ERR Current oU Detailed Hardware Description of DC AC Current Low Current Output Amplifier eese Mid Current Output Amplifier essen High Current Output Amplifier essen High Current Amplifier Power Supplies Mongo Supplies High Voltage PCA essc esee Detailed Hardware Description of the 22 V Amplifier
20. UUUUUU 8E oo Lao 512 1062 XE gt rsy Coes 2 Gesu Corsa osu 21692 Sra pad Em af ON 1 9 m ear s 8 eur Cuore era 1 ue SH EB 3883 8 88 8 6 en e I M 1 B E n E Tis 2 Figure 5 4 A5 Ohms PCA 4 RIVETS 4x 57LFC 3005 054 List of Replaceable Parts 5 Parts Lists Table 5 5 A6 Digital Synthesis PCA Ref Part Des Description Number Qty C1 C3 6 CAPACITOR SMR CAP CER 0 1UF 10 50V X7R 0805 690500 78 C8 16 C18 23 C26 28 C42 43 C45 46 C50 C54 C60 C70 CAPACITOR SMR CAP CER 33PF 5 50V COG 0805 C25 51 CAPACITOR SMR CAP TA 10UF 20 25V 6032 927814 12 C57 C59 C62 68 C96 C29 324 CAPACITOR SMR CAP CER 2200PF 5 50V COG 0805 942524 3 33 C30 31 CAPACITOR CERAMIC 100PF 596 100V C0G 0805 TAPE 601028 C36 37 CAPACITOR SMR CAP CER 100PF 1 100V COG 1206 644812
21. pue 8014 A PU A BV 2 45 apv016f eps Figure 2 7 A8 High Voltage PCA 22 V and 220 V Amplifier 57LFC AN Service Manual Detailed Hardware Description of the 22 V Amplifier The 22 V amplifier has a gain of 10 and provides output voltages of between 2 2 V and 22 V dc or ac rms at frequencies up to 100 kHz The amplifier is designed to accommodate a maximum burden of 50 mA dc or ac rms and a maximum capacitive load of 500 pF To achieve the maximum required voltage swing under ac conditions the output stage 15 operated from 45 V supply rails whilst the input stages are operated from 15 V rails All power supplies are derived externally In the 22 V range relays and route the input signal V3 3 and it s associated ground RCOM 1 from connector P108 to the inverting and non inverting inputs respectively of an operational amplifier input stage comprising U5 and U11 The combination of wide bandwidth amplifier U5 and chopper stabilised amplifier U11 allows wide bandwidth and good dc performance to be achieved simultaneously Transistors Q59 and Q60 diodesVR23 and VR24 and resistors R233 and R234 form a feedback voltage clamp around the op amp to ensure the output and inverting input always remain within their linear operating range This is necessary to prevent conditional large signal instability of the 22V amplifier resulting from the finite overload recovery time of
22. 2 9 Final Relay States by Instrument State 2 10 Functional Description of 2 11 Compliance Voltage 1065 40 1 2 10 0000000000000000000000000000050 4 2 12 OTEST Register States by Instrument State 2 13 OCHK Register States by Instrument State 2 14 Diagnostic Values by Instrument State sss 2 15 Supply Values as a Function of 3 1 Recommended Equipment for Calibration and Verification 3 2 DC Volts Measurement Limits sese nre 3 3 Volts Measurement 3 4 Frequency Values 345 4 Wire Values nie en i EE 3 6 2 Wire Ohm Values 3 7 DC Current etie rte Gaul eee FRE deae tre ose 3 8 Current 3 9 Current Output Compliance 5 3 10 Voltage Output Compliance Limits sess 3 11 Harmonic Test Values for AC 8 3 12 Harmonic Test Values for AC Current 3 2 5 l Assembly ate teret 2 5 2 2 9 5 3 A3 Motherboard eiecti idee rea eee don
23. R121 507 3D6 3A7 5 2 4 Z6 U31 MDG444 45V R86 P106 Re 5 A18 IPHASE EE 1K 5 SEC XING STROBE 545 20K 5 R85 15V 5 13 V v33 LOCAL FB 16 i MDG444 AN 15 14 16 5K y 15V 15v V ua3 TP7 11002 DIAG M TW SMUX 1 6 5169 13 933 7 DCI ACI 9 i MDG444 13 AB did DDS2 OUT 10 bau V U31 SPR eRe 1 MDG444 2 3 4 1 019 Y 25 L30 4 15V A19 IFBCK 4 15 E 220 OHM MDG444 t E aa MDG444 mt 16 5 220 220 OHM lt 7 u9 1K 5 L8 4 LTC1050 2 CD IDAC OUT M 220_OHM A CURRENT ERROR OUT 9 10 L3 R13 1 ANN 2 00K 2 00K 2 00K 150K 220 OHM 5520 8107 i 62 C67 35 0 150 T 0 150 100P 26 15V PPS PPS 3 14 1 2 096 220 OHM 3 BAS70 04 R15 R33 100P 150K 150K 26 26 59 15 1 16 7 0 150 2 00 2 0 PE S1 COMMON 57LFC 1006 4 of 8 122 220 OHM 106 19 I ACDC 2 Figure 6 4 A6 Digital Synthesis PCA cont 6 21 57LFC Service Manual
24. P106 SMUX PMUX AD 7 0 CREF CREF IG lt 7 0 gt 15V V osci 13 D7 osc2 D6 V 1082 B5 606 10 16 MDG444 BUBDUT Di 15V 15V 15 lt 14 INTOUT 22 Ms 5 11K INTIN Di 22 529 REF MDG444 MMBD1501 244 1 zl Eo 5 IG RD 385 S1 COMMON 2 15 356 INHI WR IG WR 221 R153 2A7 25 vV EOC 21 15 14 AA 5 2 AGND 220 OHM 2 5 15 11 oy DGND U30 8 MAX135C CR17 7 6 18 14 MMBD1501 A D CONVERTER 305 SMUX me 4 15V C64 m 15 827 13 E PE U82 Ve MDG444 9 GAIN 25M 11 10 15V 15V v 4 U22 l zl MDG444 15v INSTRUMENTATION AMP L20 A21 220 OHM m IDAC X2 2 VDAC X2 4 15V 15 DIAGNOSTICS CAL P106 SRC ce SRC 8B7 Cm SHORT AS SHORT OTD c5 OTD TC SRC cie TC SRC TC 15 TC COMP TC MEAS 082 TC LO A14 8B3 gt MDG444 2A4 D gt TC_LO 7 6 TC HI TC ISO 220 OHM TC ISO SRC 24 cis TC ISO SRC 15V 220 OHM ISO MEAS 1 2 TEMPERATURE SOURCING SENSING 8D6
25. 2 8B7 8C2 6D6 57LFC 1006 5 of 8 6 22 Figure 6 4 A6 Digital Synthesis PCA cont Schematic Diagrams 8 7 6 5 4 3 2 1 IG DATA lt 7 0 gt 5V 8B2 5D6 74HC374 GAIN 25M m 19 ZCAL I 16 1 Les 4692 15 FAULT CLR 7B5 0 1U 0 1U 0 1U 0 1U 0 1U 0 1U MGE OUT 305 acs 415V BLOG U83 U95 054 Uii 07 c2 CM lt 2 0 gt 2 V 7 57 8A7 REG 2 11 045 050 m R156 cii2 1 16 07 0 10 10 16 19 210 0 10 T 0 10 74HC37 4HC7 SEL 3 0 De 95 DCV ACV z 0075 2 MULT isv U90 VR1 7 6 LV ENABLE 3B8 LOOP POLARITY 555 REG WR lt 1 gt 011 COUPLE Mz 19 ENABLE opp 547 5 LOCAL AC FB Fa 14 13 12 3 8 LOCAL FB 5 J 127 14 p 10KHZ LPF 0 3 DCI ACI 1 ILOOP DIAG VLOOP DIAG orgy sps R163 ik 5 f 1 1 1 a 2 1 gt m
26. 953 545AK pBii VREF DB10 19 V DB9 DB8 DB7 DB6 DB5 DB4 1 15V 22 4 V 4 3P 4391 2 DB3 DB2 DBO WR C8 V 6 PE 15V DDS1 OUT U25 4 AD845K 15V 2 PRI CHANNEL SCALE DAC AO BO SEC_STROBE VDD IOUTA R19 VOLTAGE ERROR OUT 947 AD7628K 1 cS VREFl WR COMP DACS DB7 RFB1 DB6 DB5 DAC 5 lt 0 gt OUT1 DB3 DB2 OUT2 DBO DATA lt 7 0 gt RFB2 DACi DAC2 AGND VREF2 IG ADDR 0 1 18 R21 CURRENT ERROR OUT IOUTB 10K 5 R20 LADCOM REFADJ REFOUT REFCOM IREFIN COMP REF DES Ui I CHANNEL D A PARTNAME 7C4098 10K 55 R16 R23 51 1 49 9K U23 4 MC34081 L 7 15V U2 PLCC U7 U8 U11 374 HC 012 U15 U22 U24 U26 U29 U31 33 U46 048 082 MDG444 016 00 AC 719 04 034 16245 LCX 043 045 096 DG444 947 AD7628K U53 U56 AD7545A U54 U83 U95 UCN5800 064 14 065 DS8923A 056 AD7545AK DB11 VREF 19 DB10 DBO DB7 DB6 D
27. Standby Current A7 032d Internal Measure Opt 3 3 V A6 Output Internal Measure 2 2 V 018d Buffer Output Internal Measure 22 V A8 r r s s r s r s r 01ad Output Internal Measure 220 V 05ad A8 Output Key x don t care r reset s set d reset 0 for internal sense or set 1 for remote sense g reset 0 for external guard or set 1 for internal guard Notes Anover voltage detection or other serious problem should trip the instrument to the fault state Anover compliance or over current detection should trip the instrument to the appropriate overload fault e hardware fault causes the instrument to enter the fault state Theory of Operation A3 Motherboard PCA Table 2 4 Control Register States by Instrument State Control Register MBSW Signal CKIT CKHVCUR WARNING OPERATE STANDBY Instrument State Bit 8 4 2 1 4 2 1 hex Weight Dormant x x H H H H L 36 Fault x x H H L H L 32 Standby x x H H H H L 36 Output Ohms Current x x H H H L H 35 l orV 3ov Output V gt 30 V x x H H L L H 31 Output V lt 30 V x x L 25 Monitor HVCOM current via SMUX Output V 30 V x x H L L L H 21 Monitor HVCOM current via SMUX Output Ohms or V H H L H 15 gt 30 V Monitor Internal Temperature via SMUX Output V 30 V x x L H L L H 11 Monitor Internal Temperature via SMUX Key
28. 1 8 x M t OW OVIG 990 5 85 1 5 5 5 1 8 1 1 1 1 8 8 8 8 1 8 8 8 8 8 8 1 8 1 8 9JIM t 061 OVIA 990 8 5 1 5 5 5 1 1 1 1 8 8 8 1 8 8 1 s 2J s 2Ji si si s x 9JIM t 5461 qqop 5 5 1 8 1 1 1 8 1 8 8 8 1 8 8 8 8 8 5 8 1 1 8 1 M 0461 OvIQ qqop ps 6 5 1 5 5 5 1 8 1 1 1 8 2 1 8 8 1 1 8 061 qqop ps 5 1 5 5 5 1 1 1 1 8 1 1 1 8 9JIM t 6L pp 5 85 1 5 1 1 5 1 8 8 8 8 8 8 8 1 8 1 8 8 8 8 1 8 ARE A amp LS dwog 061 071 pp 1 1 1 1 1 5 1 8 8 8 8 8 1 8 1 8 8 1 x 061 peg 8 5 lt lt lt 5 A amp LS 001 peg 1 1 1 1 1 1 5 1 8 8 8 8 1 8 8 1 8 8 1 8 8 8 1 8 x
29. 2 2 6 t za by M 17 ex ta za za 2 P9 194516 A1HO enya Aejay 2 23 Table 2 9 Final Relay States by Instrument State cont 57LFC AN Service Manual 400002000 esn ainseow 0000 pue dwy pieng 12 0000 X X X X X X X X X X X XxX X 2J3 XxX X XxX XxX xX xX X X X x x x x x OVIG 400200000 esn 0000 JO H YA eanseeyw ooo0 x x x x x x x x 243 24 24 X X X X X X X X X X X XxX xX Auy 990 5 5 1 6 lt 85 8 1 8 1 1 1 1 8 8 8 1 8 1 8 8 8 8 8 8 1 8 1 x M t OW 61 OVIG 9909 1 8 5 1 1 11 1 11 8 8 8 8 1 8 8 8 8 8 1 8 1 sj s 1 s x aM t OW OL 990 1 5 5 5 1 1 1 1 1 1 1 8 8 1 8 1 1 8 x 9JIM t OW 61 9909 5 5 1 5 8 1 1
30. 5520A 6502 C130 0 047U T 5V U49 LF356 4 1 3 2 R199 ACDC SW 10 0K CR30 BAT54S MONGO 4 1 57LFC 1007 5 of 5 2 Figure 6 5 A7 Current PCA cont 6 31 57LFC Service Manual 4 626 229 R28 E20 E3O qa NP6 dus 1852 k23700 87 cress c72 e c VR53 065 a id wo R102 R260L1 oe d RITA R261 z s Ried x c22 cree R95 R96 0 z ESS 8145 R233 28 r135 Bes n 1 4 RIVETS 4X cones 7147 EMI em HAS S CR29 VR22 03 Bul ards ge 2 d Cinzo3 ela m 4 1 8 fA R202 oo R12 R11 R204 TT 15 UL J R38
31. 8 9 9 s v za 1 1 27 ra 27 27 zal 27 27 ia ia afal 17 pr pif sa Aeleg enu A1HO 2 21 Table 2 9 Final Relay States by Instrument State cont 57LFC AN Service Manual S S 1 5 5 5 1 s 2 s s s s s s 1 5 5 5 5 4 S x AALS AIM ON 6L 91815 SUI reale sls s 1 v OW 6 1 5 5 5 1 1 S 1 5 5 1 1 S 1 5 x 15 AIM ON OL 1 1 1 1 S S 1 s s s s 1 S S 1 S S 4 5 5 5 5 5 5 4 5 5 5 5 4 5 x IM t OW OL a 5 101 5 5 421 5 58 ss 1 s idilsi sis s 2 s 2si si s si sisix M GN 6L S S 4 5 5 5 4 5 5 5 5 4 5 5 4 5 5 4 5 5 5 5 4 5 4 5 5 5 5 5 5 x AGLS AIM t ON L 4 1 1 1 S S 1 S s 1 s s 1 S 1 s s 1 5 1 S S S s s s x AM t OW 8 8 s s s asis oum p o os 4 1 1 1 1 1 5 5 5 1 1 5 5 5 5 5 5 1 1 1 5 5 x 9JIM t 061 S s 1 S S S 1 5 5 5 5 1 5 5 1 5 5 1 5 5 5 5 5 5 1 S 1 s 1 5 5 x 15 SIM 001 uls v O01 S 1 S
32. R56 L 711 1 10 ok 2 5 2 MC33172 1 20 P106 RCOM2 c20 M1 TC LO NET PHYSICAL TYPE 50MIL RET LO S1 COMMON 5 3A7 3D6 4A7 5D7 a 210 a 10 0K 1157 5500A 8102 Tx 045 ADG411 i 2 2 16 3 210 12 Ty 15 11 10 5 5 AN 7 y 4 15 AS NP lt 0 gt U19 74HCU04 8D3 P lt 2 gt 1 2 R72 Rra 1 00M 15M 5 R70 100K 15V y SEE POWER GROUND CHART aca Pel 10 0K MeV 5500A 8102 13 ADG411 V 2 2 16 7 211 8 556 DAC2PREF 14 AS 18 34 8K 2A5 DAC2NREF 11 8 6 v 72 4 15 Ty lt 1 gt U19 74HCU04 P lt 3 gt 12 R7 R12 1 00M 15M 5 PCLK R159 R30 100K dns NPCLK NN 100 R40 OUT 206 15V 22 1 R45 046 DACIPREF b MDG444 V 129 2 220 OHM 14 15 2 203 505 9 C132 pev 11 AN 10 L 4 nA cse 2 2U PE 0 1U 5 Lu v 2 29 V 100 15v PRECISION INVERTER 52 0 001U RAs DACINREF p R61 ANN 206 15V 1 22 1 R6 Z3 AND 01 ARE PART OF SY MATCHED SET 5520A 4501 7 M3 PART NUMBER 626678 nlt RA DAC2NREF 26 6 22 1 4 LTC1150 7VREF L 3 3K 2B3 2 8842A 4R05T H 10 ca2 15 0
33. bi 2N5401 X 4 MVOUT 29 012 QE B SGND 2 0 2 2N5551 2N5401 Qa 9 os E X3 is 220VREF 2 8 A21 11 22VREF 1 SGND o 525 036 z mye 2N5551 n 9 09 N pd MMBT3904 SGND c2 154 SGND DU n SGND SASN R146 R145 ANN 10K 10K TP7 mE C4 CE L c35 TT 100 1607 TPS 10 send 16 A13 C15 45V 15V TP10 El 56 C34 C55 100 10U 15V 2577 19 0 1U 25V SGND SGND REFERENCE DESIGNATON LAST USED NOT USED CR24 28 33 34 64 P1 107 109 207 01 2 4 5 7 22 25 027 29 33 42 44 52 057 R13 21 31 35 47 59 R60 105 106 262 R263 266 276 P108 Ki C24 8 VMID R143 s Lr 10 57LFC 1008 1 of 4 2 Figure 6 6 A8 High Voltage cont 6 33 57LFC Service Manual 032 MMBT3906 220V1N VR22 1 R103 R101 048 VNO605T a EXIIT MMSZ5240BT1 iov 5 CR1 BAV99 MMBT3904 R197 3 57K 1 1 045 MMBT3904 CR46 MP10 TIP31C R130 VR42 ANN 4 7K 5231 5231 5 1V 5 5 1V 5 2K 1c CBE 220VREF aS MMBT3906 054 CR2
34. 2 50 2 50 TO220HS TO220HS 957 042 HVINT POS S1 ci HVREG POS oi HVINT NEG 57LFC 1008 3 of 4 8 7 6 5 4 3 2 Figure 6 6 A8 High Voltage PCA cont 6 35 57LFC Service Manual 5RLH IG DATA lt 7 0 gt CLR_DRVR 97 74HC138 l 75 i 10U 0 1U 25V DGND DGND VDD P5V GND DGND U12 UCNS800L VCC P5V GND DGND IG CSO 74HCUO4 U6 VCC P5V GND DGND RLY RST VDD P5V GND DGND c2 5V A18 HE To TP15 714 74HC374 SPARES 74HCU04 U6 2 4 VCC P5V GND DGND VCC P5V GND DGND VCC P5V GND DGND VCC P5V GND DGND 10 VCC P5V GND DGND MBRS140 CR48 MBRS140 VCC P5V GND DGND NOLOAD 8 2V gt 5237 5 MP6 025 MP7 85 MP9 U27 T i LM35D 1 926 0 10 1 LM35D 0 1U 1 LM35D 028 10 1 LM35D VS U18 NOLOAD DG408DY VS as ni VS U19 DG408DY NOLOAD
35. AD823 SMR IC OP AMP DUAL RAIL RAIL 16 MHZ SO8 642709 4 U58 59 IC ANALOG SWITCH ADG431 5 44V 24 OHMS SPST NO SO16 TAPE 689844 1 030 034 RELAY SOLID STATE 1FORM A 80VDC 120MA 687217 3 038 031 037 IC OP AMP LT1630 2 7V 15V 525UV OFFSET 15MHZ R R S 2075118 S DUAL SO8 TAPE aa aall U52 53 DRIFT CHOPPER DIP8 TUBE ZENER UNCOMP MMBZ5237B 8 2V 5 20MA 225MW SOT 23 TAPE 837146 2 VR5 ZENER UNCOMP MMBZ5231B 5 1V 5 20MA 225MW SOT 23 TAPE 837179 4 ZENER TRANS SUPPRESSOR 6V 508655 CONNECTOR JUMPER COPPER TIN 1206 SURFACE MOUNT T R 2061468 SUBSTRATE ASSEMBLY 945316 1 THIN FILM HERM RESISTANCE REF 2094985 1 5 37 57LFC AN Service Manual CAUTION SUBJECT TO DAMAGE BY STATIC ELECTRICITY MP5 MP6 5 8 ru Cun Cuz m H14 H15 1957 085012 6 E mo Tas veel 008 H12 H13 ER Z De 57LFC 4007 apvO56f eps Figure 5 6 A7
36. Q41 42 TRANSISTOR SI N DMOS FET DEPL TO 92 945050 RESISTOR METAL FOIL 0 1 0 1 1W 10PPM RADIAL BULK 2061053 RESISTOR SMR RES MF 10K 0 1 125W 25PPM 1206 106366 5 33 57LFC AN Service Manual Table 5 6 A7 Current PCA cont RESISTOR SMR RES CERM 1K 1 125W 100PPM 1206 783241 RESISTOR CERMET 100 1 0 125W 100PPM 1206 TAPE 867494 807172 R6 R15 RESISTOR SMR RES CERM 13K 1 0 1W 100PPM 0805 930164 R64 65 R8 R108 RESISTOR 200 1 0 125 100 1206 783258 R9 R28 RESISTOR SMR RES CERM 2 2M 5 125W 200PPM 1206 811778 R156 R10 R87 RESISTOR RC1206 6 04K 1 25PPM 1760171 EH RM RESISTOR SMR RES CERM 270 596 125W 200PPM 1206 746354 5 34 List of Replaceable Parts 5 Parts Lists Table 5 6 A7 Current PCA cont Ref Part Des Description Number Qty RESISTOR SMR RES MF 1K 0 196 0 125W 10PPM 1206 929880 R23 R32 R32 RESISTOR SMR RES CERM 121 RESISTOR SMR RES CERM 121 1 063W 100PPM 0603 063W 100PPM 0603 689122 2 R24 4 RESISTOR CERMET 0 060 5 0 5W 100PPM 2010 TAPE 105999 R61 62 R26 R54 RESISTOR SMR RES CERM 10K 1 125W 100PPM 1206 769794 RESISTOR SMR RES CERM 316 1 125W 100PPM 1206 604900 R37 RESISTOR SMR RES CERM 2 61K 1 125W 100PPM 1206 781179 2 R38 RESISTOR SMR RES CERM 698 1 0 1W 100PPM 0805 641156 4 R44 RESISTOR SMR RES CERM 511 1 125W 100PPM 1206
37. R99 CAR102 105 O B R142 90 Rios 062 R100 J 61 R86 5 SUBJECT TO DAMAGE BY STATIC ELECTRICITY E Cores Corso 2891 BB apago 5 05 rus E23 Ri 1 0 205549 s ED ce C59 sets Cen B38 6 17 Figure 6 4 A6 Digital Synthesis PCA 57LFC Service Manual PRI lt 15 0 gt DDS CLK OUT VDD IOUTA IOUTB LADCOM REFADJ REFOUT REFCOM IREFIN COMP V CHANNEL D A _ lt 15 0 gt DDS CLK OUT SCALER OUT 11 0 PRI STROBE IDAC X2 2C3 5 7 10KHZ LPF LF HF OFF EN HF LF 1734 74LCX16245 U34 74LCX16245 TT A7 B7 A6 B6 A5 B5 4 2 2 1 R141 7 50K
38. Te 1 RST SET RST CSET RST CSET RST CSET RST CSET RST CSET TRST SET U83 UCNSBO DE 15 16 15 16 15 16 15 16 15 16 15 16 15 16 9 10 11 12 064 74ACT14 RELAY WR lt 1 gt ai 14 954 UCN5800L 9 10 1 1 11 12 064 74ACT14 RELAY WR lt 0 gt 3 gt 4 spe U95 UCN5800L 10 CLR DRVR 7 7 P206 A A30 57LFC 1006 6 of 8 C29 A29 8 7 6 5 4 4 a 2 Figure 6 4 A6 Digital Synthesis PCA cont 6 23 57LFC Service Manual 499 100K 11 1 BATSAA C140 SPARES D T 15V 0 01U pr P206 m c100 i ANN Du 0 010 EX I 9 DS8923A DDS SYNC IN 055 CLIN A Al 5 12 H 923A 2 3 U66 T Y 4 LM358 DDS SYNC OUT RE AW U65 058923 CLOUT B M ie oro DDS CLK OUT di 15V 265 108 DS8923A 11 8 CLOUT A 2 4 lt 3 4 U87 y TL062 AN T2 22 1 gu PE 65728T 805 C133 019 PE 65728T SER CLK 10 R103 1 ANN Uxc 856 7 10 0 01U 499 R97 SER CLK B
39. 9 TIG B CPU 10 15MIL 11 15MIL TIG A 12 FIG A 74HCU04 ENCSIG 3 4 U8 B UCN5800L ENCRESET 2c4 5VG 1 203 12VG 12VG 7 6 9 1 2 1 2 203 4 36 G 12 5 i 19 Lea R 1 CLR 06 SET RST SET RST STB UCNS800L DS2E1 16 15 16 15 15MIL 5 UNR ENCODER 3 6 9 gt 5 our 19 ENCRESET 45v 1 1 11 15M UNUSED 5VG 0 12 ENCSIG 74HCU04 IN OUT UA 1 74HCU04 74HCU04 T 0 10 2 gt 09 UA T DS STB UCN5800L CRO CR13 12 9 8 BAV74 BAV74 BAV74 29 74HCU04 10 R13 A 1 00K Y 57LFC 1003 Figure 6 2 A3 Motherboard PCA cont 6 10 6 Schematic Diagrams 57LFC 7605 2 yeI Eu 162 28201 123 se 220 _ 1022 926 027 822 622 612 062 693 R10 R11 0337 9349
40. I C84 CR52 R53 0 10 GF1G 2 1007 031 MJE15028 TO220 HSNK 3 6 CR28 C57 U31 GF1G 1N979B 1 BAV74 MJE15028 TOOMIL 100P 5ev 7 TO220 HSNK 15 3D8 5 100MIL 100MIL 15 C58 012 TP21 GUARD 147 MPSA42 R54 R48 TEN 45V CR76 CR73 SEE VR10 12V s SECONDARIES 104007 104007 SMBJ12A CR70 CR72 CR45 R64 L C73 180UNR Bavies Me L C36 VR11 P2 SEZ00A 560K SP 300 47U 1 1N4007 1N4007 90 0K 50V 5 TP27 TP28 1 58MC47A 3 4 T15AC2 3B8 s 6 15 1 T SHIELD 8 GUARD SHIELD R91 L C91 KEY F3 470 10 360AC2 1 2 0 5W 400V 330U C85 1 58 47 11 1 0 2 524005 100V T 1000 167 12V 14 45ACL 5 180 1 SMBJ12A 60 FL 45V srmn SEINE 1 2 018 013 0 2 R92 1 C92 UIS AME 2N6520 2N5401 FROM POWER XFRMR 5eok T igov 0 5W R85 1N4572 F5 100K 150 CR44 2 c1oi VR2 2 032 SP200A SPZ00A 330U CR26 0 2 AMP 1 15029 100V R88 R76 6 T0220 HSNK 100K 10K 1N979B 1 U32 14 Bev 53 MJE15029 R65 4 47U 2 TO220 HSNK Seok aoov A SEZ008 1N4007 1N4007 33 59975 TP 1 EA 3 57LFC 1 003 SP400A P2007 360UNR 0 2 AMP 1N4007 1N4007 zr X Bl 2 of 5 8 7 6 5 5 4 3 2 Figure 6 2 A3 Motherboard PCA cont 57LFC Service Manual 8 7 6 5 4 3 1 CR41
41. R89 ica lt gt CET HICURRENT AMP IN 2 2A OUT lt gt R95 698 2 2A ENABLE AQV225 R207 R208 49 9 49 9 MP2 TEMP MP3 TEMP 15028 5 TEMPERATURE SENSING CIRCUITRY 012 MMBT3906 57LFC 1007 2 of 5 2 Figure 6 5 A7 Current PCA cont 6 28 Schematic Diagrams LOCURR OUT agas MID CURR RTN ice LOCURR RTN HI CURR RTN SOFT START COMPLIANCE VOLTAGE LF412A 916 1 49 9K CR17 DB101S 115908 6v 105 49 9K LOW CURRENTS MONITOR 2 2A ENABLE COMPLIANCE MONITOR 45V R115 10 0K RECTIFIER TP10 5169 RECTIFIER IH 045 10 0K C58 T 33U PEAK TP11 ec R193 TLP124 10 0K 15V 020 T LM393DT 4 920 1 4 LM393DT I SHLD All cu 57LFC 1007 3 of 5 2 Figure 6 5 A7 Current cont 6 29 57LFC Service Manual 74ACT175 220MA COMP 2 2A ENABLE 2 2 ENABLE 698 R42 AN MID CURR
42. 4 4 7 Chapter 5 List of Replaceable Parts Title Page Introduction u ul 5 3 How to Obtain Parts 5 3 Service Centers iie recita Pere ave ee eap 5 4 Pais 5 4 5 1 57LFC AN Service Manual 5 2 List of Replaceable Parts 5 Introduction Introduction This Chapter contains a list of field replaceable parts for the Calibrator Parts are listed by assembly Each assembly is accompanied by an illustration showing the location of each part and its reference designator The parts lists give the following information An indication if the part is subject to damage by static discharge Description Fluke item number Any special notes 1 e factory selected part The replaceable parts list is limited to removable module assemblies and ancillary hardware such as screws nuts and structural parts that may become damaged or lost during repair or shipping The Calibrator is intended to be repaired to the component level by Fluke authorized personnel only All others are encourage to localize faults to the module assembly and then to exchange the assembly through the Fluke Product Exchange System Note Once parts have been replaced the Calibrator must be fully adjusted and verified to be within manufacturer s specification before being returned to normal use A AACAUTION The Calibrator may be damaged by static discharge if improperly handled How
43. 5 5 V 5 5 4 3 U10 C29 lt R32 i 2 R28 R110 0 1U 4 ANY ANY LM339 49 9K 4 99K 27 CR85 100 R21 0 1U BATSA4A V ues V R27 45V 206 45V 45V 26 d R112 RY 0 1U 10 0 10 0K R114 R113 11 U10 sn 012 AN F 33 RAO 100 4 99K m ____ 4 C116 CR86 T 10 0K TS 45 C115 Ree 12 LM339 R35 9 49 0 65 3 01K OVER22V iov 10 0K _ 010 4 LM393DT 45V 9 3 C32 CR87 14 0 19 R36 54 8 10 0K Ce eS 150K 1 57LFC 1 003 R116 R117 C117 49 9K 499K n V 3 of 5 15V 8 7 6 5 4 4 3 2 Figure 6 2 Motherboard cont Lo 07 5 4 P3 5 c2 TP15 100MIL 1N5822 CR60 t 1 ews 100MIL 22V 1 100 20 0 19 1 U34 2 RFP70N3 CR61 8 MMACI 4 19 9 TO220HS RTE 100MIL VRS A Bd 100MIL 100MIL 5245 isv 4 7008 02 TRla 16V 9 6 _ TMMCOM MMCOM 100MIL 1142 M6 L 151 UNR T 4 700E 02 2 TP12 CR37 16y V23 100MIL 100MIL T o 1U R81 4 LM393DT 4 99K MMCOM 0 1U 15
44. 5 TND ISELUA ISELTUA TRY LSELMA 10 0K HARDWARE FAULT TRIP POINT C51 11 51V IZGRD 0 1U TRIP POINT AN 4 34 5V as Ty ie 14 FAULT 2 57 1005 3 of 5 6 14 Figure 6 3 A5 Ohms PCA cont Schematic Diagrams 8 7 6 5 V 4 3 2 1 TOP SHIELD MBRS140 5 MBRS140 U39 74HC374 ISELMA ISELHUA ISELTUA ISELUA ISELHNA ZIVREF INIVREF INRCOM R41 ANN 2 00K C76 U35 100P 7AHC374 CR8 BAV74 A18 IG CS6 CKIVREF CKHI CKLO CKCOMPV CKEXTRA ENCOMPFAULT TG CS5 PULL DOWN CET sas R42 1 00K V 57LFC 1005 A23 RLY RST 4 of 5 8 7 6 5 4 3 2 Figure 6 3 A5 Ohms PCA cont 6 15 57LFC Service Manual 4B7 IG ADDR 2 IG WR IG CS5 AAT IG DATA 7 5 c90 U37 74HC138 T 7 7 4 312 314 1i 45 ___ 11 74HCU04 U33 10 UCNS800L UCNS800L UCNS800L 74HCU04 U
45. 8508A Connections to the 57LFC for AC Current Measurement 8508A Connections to the 57LFC for Load Current Compliance Test 8508A Connections to the 57LFC for Voltage Compliance Testing Harmonic Test MEL 3 1 Replacing the 5 4 4 Accessing the Air Filter eti age Exploded View of the Calibrator essen 4 0 Final Assembly uu AVEED PCA CL IP 2 9 Motherboard PEA eret tree Ere AS Ohms PCA rr AG Digital Synthesis PCA A weise EEE High Voltage E AD Out Guard dee e EE ao AT LED PCA DIR Motherboard AS Ohms PC e ie Digital Synthesis C rrent EP 8 High Voltage PCA A9 Out Guard CPU PCA UI sc ce to sen Vil 57LFC AN Service Manual viii Chapter 1 Introduction and Specifications Introd cti R en N rende Service Information A CCESSOTICS eredi REGI bee aereis Low Thermal EMF Test 8 Rack Mount Kit i eene eedem Shielded IEEE 488 Cables
46. BELLE EIER EET AnyQ 24 W STBY Q 2 4 W STBY Any Q 2 4 W 3a Measure Vcompl Any x x Measure Ivref 2 30 Theory of Operation A5 Ohms PCA Table 2 13 OCHK Register States by Instrument State cont Control Control Register OCHK CK CKHI CKLO CK IVREF EXTRA COMP FAULT Instrument State 1 Bit Weight DIAG Any Q 37 Measure LO DIAG Any Q Measure HI DIAG Any Q x x h h h L h h 3b Measure Vcompl Key x don t care h high off de asserted L low on asserted Notes Only one of the CKx lines can be asserted low at a time to switch a signal onto the SMUX line for measurement 2 31 57LFC AN Service Manual Table 2 14 Diagnostic Values by Instrument State IDAC OTES Ivref LO Limit X2 T Reg Instrument State Test Vdc Hex SMUX SMUX Vdc Current Vdc mmm wm ofp Monitor Comp Msr Vcompl ama see oor 2000 0 00 DIAG 1 9 Check Ivref LO or HI 2 000 0 001 Key doesn t apply 1 30 mV 4 300 mV 12 V full scale can be measured the SMUX line 2 Oto 3 3 V is the range of voltages that can be output on ACDC 2 32 Theory of Operation A6 Digital Synthesis PCA A6 Digital Synthesis PCA The A6 Digital Synthesis PCA contains the following functional blocks
47. CKVATEMPS SMU OUT Uio ADG413 VA I POS VA I NEG VCC P5V GND DGND 2 57LFC 1008 4 of 4 6 36 Figure 6 6 A8 High Voltage PCA cont Schematic Diagrams 6 6 VIE CAUTION SUBJECT TO DAMAGE BY STATIC ELECTRICITY NOTES 1 FOR SCHEMATIC DWG SEE 571 1009 2 ASSEMBLE PER 0 5 0 111 1 4 REMOVE AND DISCARD amp H002 AFTER ASSEMBLY 5 gt MARK ASSEMBLY REVISION LETTER IN LOCATION SHOWN USING A PERMANENT BLACK FELT MARKER 6 gt 22 4 11 ARE NOT INSTALLED 57LFC 7609 1 of 1 3 Figure 6 7 A9 Out Guard CPU PCA 6 37 57LFC Service Manual
48. The relay matrix is shown on Sheet 1 of the A3 Motherboard PCA schematic and the relay control is shown on Sheet 5 Some of the purposes of the relay matrix are to provide isolation between the output binding posts and the internal circuitry during standby and provide isolation when running zero calibration or diagnostics The functions of the relays are shown in Table 2 1 The relay control circuits consist of U3 U5 U6 U8 and U9 For U3 74HC138 the CSI signal is generated on the Digital Synthesis U8 selects the driver latch used to set or reset the latching relays 2 5 57LFC AN Service Manual Table 2 1 Functional Description of A3 Motherboard PCA Relays Relay K1 Functional Description Reset connect LO s to the A6 Digital Synthesis PCA connect OUT LO to the A6 Digital Synthesis LO and connects SNS LO to the SNS LO Set disconnect LO s from the A6 Digital Synthesis PCA disconnect the A6 Digital Synthesis LO and SNS LO from the LO input terminals K2 Reset select internal sensing connect OSNS HI to IN SNS HI and OSNS LO to IN SNS LO Set select remote sensing connect SNS HI to IN SNS HI and SNS LO to IN SNS LO K3 Reset connect the Digital Synthesis PCA divider connect IN SNS HI to the A6 VDIV Set disconnect the Digital Synthesis PCA divider disconnect IN SNS HI from VDIV K4 Reset select VMID for output connect VMID to OUT HI Set
49. WHITE BROWN WIRE FROM TRANSFORMER WHITE BLACK WIRE FROM TRANSFORMER BROWN WIRE FROM TRANSFORMER WHITE BLUE WIRE FROM TRANSFORMER HITE WIRE FROM TRANSFORMER BLACK WIRES FROM TRANSFORMER MP14 H9 57LFC 120 2 of 2 apv051f eps Figure 5 1 Final Assembly cont 5 8 List of Replaceable Parts Parts Lists Table 5 2 A1 LED PCA Part Number Qty LEDREDRIGHTANGLE20MCD RED RIGHT ANGLE 3 0 MCD 927389 LED YELLOW HLMP 1401 2 2MCD 10MA 1 5 2 4V 60 DEG VIEW chu dd T1 RT ANGLE BULK 914242 LEDGREENRIGHTANGLE26MCD GREEN RIGHT ANGLE 2 6 MCD P MERI CAUTION SUBJECT TO DAMAGE B STATIC ELECTRIC 57LFC 4001 1 of 1 apv052f eps Figure 5 2 A1 LED PCA 5 57LFC AN Service Manual Table 5 3 A3 Motherboard PCA Description Number Qty C1 C3 CAPACITOR SMR CAP TA 4 7UF 10 35V 6032 605441 15 19 CAPACITOR SMR CAP CER 0 1UF 10 50V X7R 1206 605292 F C8 C11 12 C17 18 C20 27 C29 C32 35 C38 C41 45 46 48 49 C51 52 C55 56 C58 C60 C62 68 C75 79 82 C88 89 C95 96 C99 100 C102 107 C116 120 C122 C57 CAPACITOR CERAMIC 100PF 5 100V COG 0805 TAPE 601028 CAPACITOR SM
50. schematic The floating 3 75 5 V power supply is generated by transformer full wave rectifier bridge and a number of 1000 uF capacitors as regulated by Q1 Q2 U24 and associated components along with the R23 R20 resistor divider set the positive regulator output VR1 along with R30 R18 R16 and R19 set the negative regulator output Monitor The embedded software continually monitors specific hardware aspects when in operate In ohms monitoring protects the instrument from damage and particularly the high performance Fluke resistor networks from damage This is accomplished by checking the compliance voltage against the appropriate limit on a regular basis Short term overloads below the hardware trip threshold will be allowed while longer period over compliance voltages will cause the instrument to go to Standby Whenever sourcing a resistance e ENCOMPFAULT line will be asserted so that excessive compliance voltages above 33 V will quickly cause the hardware to trip out the instrument The compliance voltage is measured regularly using the SMUX line when in Operate The absolute value of the measurement is internally compared with the SMUX limit given in Table 2 12 for the appropriate resistance output If too many consecutive measurements exceed the limit meaning the compliance voltage has been too high for over 2 5 seconds then the software will generate an over compliance error and put the instrum
51. Mid Current Amplifier IGND High Current Amplifier Shunt Amp IFBK Us Shunt Resitors apv015f eps Figure 2 6 AC Current Functions 2 39 57LFC AN Service Manual Detailed Hardware Description of DC AC Current Current returning from the output load is sensed by current shunt R1 for the 2 2 A range by the 4 shunt in R net Z2 for the 220 mA range by the 40 shunt in R net Z2 for the 22 mA range by the 400 Q shunt in R net Z2 for the 2 2 mA range and by the four resistors in series 4 total R19 R20 R52 R155 for 220 range Solid state switches U23 U10 and U28 select the shunt required by each range The SHUNT SEL lines from the digital control circuits activate the switches for the range required Both the Hi and Low sides of the shunt are selected in pairs The shunt voltage is amplified by a differential amplifier composed of amplifiers U33 048 U53 052 and associated components R net 74 sets the gain of the differential amp to 2 5 Amplifier 029 cancels any current in the RCOMI line 033 provides an additional gain of 4 to the 2 2 A range shunt voltage so that a smaller value shunt could be used for less power dissipation The output of the differential shunt amp is fed back to the A6 Digital Synthesis PCA on the IFBCK line the OS line via solid state switches 025 U27 and to the distortion loop error amp U18 via resistor R3 The feedback from the differen
52. Resistance Accuracy Absolute Uncertainty of Nominal Resistance Characterized Value Full Specification Maximum Peak Value tcal 5 Current Current hace enn 1 Year 1 Discrete resistors with characterized values stored in non volatile memory Specifications apply to the characterized value using 4 wire connections Two Wire Active 2 Active two wire compensation may be selected for values up to 190 kQ Active compensation is 11 mA load and 2 V burden minimum 1 7 57LFC AN Service Manual AC Voltage Accuracy Absolute Uncertainty Maximum Ranges Frequency tcal 5 Resolution Burden 2 output V 1 year 10 mV to 22 mV 10 Hz to 45 Hz 0 1596 20 uV 45 Hz to 20 kHz 0 0896 20 1uV 50 Q output 20 kHz to 50 kHz 0 25 20 impedance 22 mV to 200 ium 50 0 output impedance 0 22 V to 2 2 V 10 Hz to 45 Hz 250 uV 45 Hz to 20 kHz 0 05 100 er 20 kHz to 50 kHz 320 pV 50 to 100 kHz 0 25 2000 2 2 V to 22V 10 Hz to 45 Hz 45 Hz to 20 kHz 0 05 100 pV 50 mA 20 KHz to 50 KHz 50 kHz to 100 0 25 22 V to 220 V 10 Hz to 45 Hz 45 Hz to 20 kHz 0 0596 20 kHz to 50 kHz 0 2596 50 kHz to 100 1 Remote sensing provided on all but 22 mV and 220 mV ranges Maximum output current is reduced by 50 above 40 Maximum load capacitance is 500 pF 2 V x Hz limited to 11 866 Note Frequency uncertainty is specified t
53. Two 4 ft 122 cm cables and One 2 ft 61 cm cable Y8021 IEEE 488 Shielded Interface Cable 1 Meter Y8022 IEEE 488 Shielded Interface Cable 2 Meters 5537 Rack Mount Kit for 57 and 5500A Low Thermal EMF Test Leads Two types of low thermal test leads are available These cables are designed to exhibit low thermal emfs The types available are e Model 54404 7002 Low Thermal Test Lead cables with banana plugs Set includes one 4 ft 122 cm cable and two 2 ft 61 cm cables Each cable includes two conductors and a shield lead e Model 54404 7003 Low Thermal Test Lead cables with spade lugs Set includes two 4 ft 122 cm cables and one 2 ft 61 cm cable Each cable includes two conductors and a shield lead Shield lead has a banana plug connector Rack Mount Kit The rack mount kit provides all the hardware necessary to mount the 57LFC Rack mount instructions are included with each kit Shielded IEEE 488 Cables Y8021 Y8022 and Y8023 Shielded IEEE 488 cables are available in two lengths See Table 1 1 The cables attach the calibrator to any other IEEE 488 device Each cable has double 24 pin connectors at both ends to allow stacking Metric threaded mounting screws are provided with each connector Figure 4 2 in Chapter 4 shows the pinout for the IEEE 488 connector Introduction and Specifications Contacting Fluke Contacting Fluke Calibrators delivered to the Navy contractors and subcontractor
54. ZENER UNCOMP BZG03 C150 150V 8 5MA 1 25W SOD106 TAPE 2060212 ZENER UNCOMP MMBZ5237B 8 2V 5 20MA 225MW SOT 23 TAPE 837146 ZENER UNCOMP BZG03 C200 200V 6 5MA 1 25W SOD106 TAPE 2113707 VR15 ZENER UNCOMP MMSZ5245B 15V 5 8 5MA 500MW SOD 123 TAPE 2062810 3 VR16 VR18 VR19 ZENER UNCOMP MMSZ5226B 3 3V 5 20MA 500MW SOD 123 TAPE 641925 5 52 List of Replaceable Parts 5 Parts Lists Table 5 7 A8 High Voltage PCA cont Ref Part Des Description Number Qty ZENER UNCOMP MMBZ5231B 5 1V 5 20MA 225MW SOT 23 TAPE 837179 VR36 ZENER UNCOMP MMSZ5263B 56V 5 2 2MA 500MW SOD 123 TAPE 2060247 2 VR37 VR54 ZENER UNCOMP MMBZ5240B 10V 5 20MA 225MW SOT 23 TAPE 783704 2 VR55 VR56 ZENER 1N6456A A52R ZENER TRANS SUPPRESSOR 400V 5 845003 2 VR59 VR57 ZENER UNCOMP 1 5SMC47A 47V 5 1MA 4W TRANSIENT 2086534 2 VR58 SUPRESSOR SMC TAPE 5 53 57LFC AN Service Manual CAUTION SUBJECT TO DAMAGE BY STATIC ELECTRICITY 889 Raz 43 23 TRA CETT 5 E pj Ema nm ees taa vide seca Bf
55. 0 25W 100PPM 1206 TAPE 2113688 RESISTOR CERMET 27K 596 0 125W 200PPM 1206 TAPE 740530 RESISTOR CERMET 18 2 1 1W 100PPM 2512 TAPE 2052279 RESISTOR SMR RES CERM 47 5 125W 200PPM 1206 746263 RESISTOR CERMET 15K 5 0 75W 200PPM 2010 TAPE 2090984 R123 RESISTOR SMR RES CERM 2 2K 5 125W 200PPM 1206 746479 Ref Des R124 R125 R127 R126 R198 R128 R132 R139 R213 R135 R147 R206 R141 R143 R145 R146 R148 R161 R168 R169 R183 R185 R184 R192 R193 List of Replaceable Parts Parts Lists Table 5 7 A8 High Voltage PCA cont Part Description Number Qty RESISTOR CERMET 3 92K 1 0 125W 100PPM 0805 TAPE 1591284 RESISTOR BULK METAL FOIL 100K 2114847 2 0 1 0 6W 0 6PPM RADIAL BULK RESISTOR CERMET 220 1 0 25W 100PPM 1206 TAPE 2063572 RESISTOR SMR RES CERM 30 9K 1 0 1W 100PPM 0805 928838 EN 1 RESISTOR CERMET 4 75K 1 0 1W 100PPM 0805 TAPE 2063107 RESISTOR CERMET 2K 1 0 1W 100PPM 0805 TAPE 928742 RESISTOR CERMET 237 1 0 1W 100PPM 0805 TAPE 801990 RESISTOR SMR RES CERM 13 3K 1 0 1W 100PPM 0805 928809 RESISTOR SMR RES CERM 10 5 1W 200PPM 2512 886705 RESISTOR BULK METAL FOIL 10K 0 1 0 6W 0 6PPM RADIAL BULK 2114858 2 RESISTOR SMR RES MF 1K 0 1 0 1W 50PPM 0805 802469 RESISTOR SMR RES CERM 301K 1 0 1W 100PPM 0805 602711 RESISTOR SMR RES CERM 200K 1 0 1W 100PPM 0805 928882 RESISTOR SMR RES CERM 15K 1
56. 125W 100PPM 1206 769810 RESISTOR SMR RES CERM 100 1 1W 100PPM 2512 691394 2 RESISTOR SMR RES CERM 332 1 125W 100PPM 1206 644614 RESISTOR CERMET 100 1 0 25W 100PPM 1206 TAPE 2090991 4 RESISTOR SMR RES CERM 1 5K 1 125W 100PPM 1206 810630 1 o N RESISTOR SMR RES CERM 432 1 125W 100PPM 1206 811885 1 5 5 49 57LFC AN Service Manual Table 5 7 A8 High Voltage PCA cont Ref Part Des Description Number Qty R194 RESISTOR SMR RES CERM 86 6 1 0 1W 100PPM 0805 106929 R195 RESISTOR CERMET 3 57K 1 0 1W 100PPM 0805 TAPE 943022 R196 RESISTOR CERMET 750 1 0 1W 100PPM 0805 TAPE 1292158 1 R197 RESISTOR VARIABLE CERMET 2K 20 0 25W SINGLE TURN TOP 1292409 ADJ 4MM TAPE R199 RESISTOR SMR RES CERM 2 43K 1 0 1W 100PPM 0805 928754 3 R201 R210 R200 RESISTOR SMR RES CERM 27 4K 1 0 1W 100PPM 0805 930185 R202 RESISTOR SMR RES CERM 18 2K 1 0 1W 100PPM 0805 930177 R208 RESISTOR SMR RES CERM 1 5K 1 0 1W 100PPM 0805 688884 R211 RESISTOR SMR RES CERM 3 32K 1 0 1W 100PPM 0805 930099 3 R264 R265 R235 RESISTOR CERMET 24 3K 1 0 1W 100PPM 0805 TAPE 943071 R236 RESISTOR SMR RES MF 10K 0 1 0 1W 25PPM 0805 650389 RESISTOR SMR RES CERM 249K 1 125W 100PPM 1206 821306 R245 RESISTOR SMR RES CERM 2K 1 125W 100PPM 1206 807172 R251 RESISTOR CERMET 2 21K 1 0 1W 100PPM 0805 TAPE 928747 R260 RESISTOR CERMET 5 6 1 0 25W 100PPM
57. C38 39 CAPACITOR SMR CAP CER 330PF 5 50V COG 0805 512038 C 34 40 CAPACITOR SMR CAP CER 1000PF 196 50V C0G 1206 867668 2 C117 44 CAPACITOR CERAMIC 10UF 20 10V X5R 1210 TAPE 1589417 5 23 57LFC AN Service Manual Table 5 5 A6 Digital Synthesis PCA cont Des Description Number Qty C49 CAPACITOR SMR CAP CER 0 47UF 10 16V X7R 0805 mm smemrsmoemenrememam wem i CAPACITOR SMR CAP CER 56PF CAPACITOR SMR CAP CER S6PF 5 50V C0G 0805 50V C0G 0805 887901 C69 C71 CAPACITOR SMR CAP TA 100UF 20 16V 7343 803822 C78 C80 CAPACITOR ELECTROLYTIC TANTALUM 150UF 1279156 20 20V 7260 TAPE C131 CAPACITOR SMR CAP CER 10PF 1096 50V COG 1206 747311 132 C135 CAPACITOR SMR CAP CER 0 033UF 10 200V X7R 1206 602547 CR1 10 DIODE SI PN MMBD1503A 150V 200MA DUAL SERIES LOW 928143 CR12 LEAKAGE SOT 23 TAPE CR14 15 CR21 CR11 A52R REG DIODE 2MA 10 DO 7 686714 CR16 DIODE GF1B SMR DIODE SI 100V 1A DO 214 912451 4 CR18 CR24 25 CR17 DIODE SI PN DF01S 100V 1A BRIDGE 4 PIN SURFACE 912456 ae MOUNT TA CR27 28 28 DIODE MBRS140 SMR DIODE SISCHOTTKY 40V 1A D0 214AB MBRS140 SMR DIODE SI SCHOTTKY 40V 1A DO 214AB 605821 ES CR29 30 DIODE SI SCHOTTKY BAT54S 30V 200MA 5NS DUAL SERIES SOT 929745 a TAPE SURGE PROTECTOR 90V SURGE PROTECTOR OOV 20 198507 EB H12 15 DIA 344 L SEMI TUBULAR OVAL HEAD 838458 l4 K1 2 K5 RELA
58. General Specifications eret Accuracy Specifications 1 DC Voltage rater Curent A Resistance Accuracy Voltage TCI 1 8 AC Voltage Distortion 1 9 NN ERE AI Re AC Current Distortion iecit enean asina eaae dee 2 Theory of c IntrOQUCLIOD 2 ioter peste ed 2 3 ALLEDIPCA U S s L 2 2 Motherboard 2 1 2 4 4102412 40000000000000000000000000000000000000000000000 2 7 Relay Control and Switch MatrIX a as LED Control and Output Cables SPEM mm Low Volt Butter u aw utu eie ret ert iaa eee rae rue In guard Power Supplies Outguard Power Miscellaneous Circuits Troubleshooting Test Points sasa List Of u y AS Ohms POA n i Precision Resistor 57LFC AN Service Manual Relay Switch Matrix and Control a sas Other Control Circuits aee
59. Protective ground earth terminal Functional earth terminal P Caution risk of danger Refer to the manual to maintain the safety provided by the equipment AVA Warning Do operate this calibrator in a position where it is difficult to operate the power switch e Do not operate this calibrator in a manner not specified in the manual or the protection provided by the equipment may be impaired Do notoperate the calibrator if it shows signs of damage or malfunction the protection provided by the equipment may be impaired Do notuse hook up wire on the calibrator with an insulation or current rating of less than the calibrator output Power Source The 57LFC is intended to operate from a power source that will not apply more than 246 V ac rms between the supply conductors or between either supply conductor and ground A protective ground connection by way of the grounding conductor in the power cord is essential for safe operation Use the Proper Fuse To avoid fire hazard use only the fuse specified on the line voltage selection switch label and which is identical in type voltage rating and current rating Grounding the 57LFC 57LFC is Safety Class I grounded enclosure instruments as defined IEC 61010 27 Edition The enclosure is grounded through the grounding conductor of the power cord To avoid electrical shock plug the power cord into a properly wired earth grounded receptacle be
60. R88 R114 R31 R117 RESISTOR SMR RES CERM 499K 196 125W 100PPM 1206 821678 R34 R36 RESISTOR SMR RES CERM 10K 1 125W 100PPM 1206 769794 18 40 41 R59 R68 R70 R73 74 R77 R94 95 R100 R107 108 R112 R118 119 R35 R72 RESISTOR SMR RES CERM 3 01K 1 125W 100PPM 1206 604329 42 43 RESISTOR SMR RES CERM 1 5 125W 400PPM 1206 690492 7 R86 R120 123 R44 45 RESISTOR SMR RES CERM 4 99 1 125W 400PPM 1206 603271 R48 R57 R46 47 RESISTOR SMR RES CERM 2 2M 5 125W 200PPM 1206 811778 R49 R54 RESISTOR SMR RES CERM 100 5 125W 200PPM 1206 746297 R52 RESISTOR SMR RES CERM 200 1 125W 100PPM 1206 772798 RESISTOR SMR RES CERM 604 1 125W 100PPM 1206 644689 R55 56 RESISTOR SMR RES MF 90K 0 1 0 125W 25PPM 1206 106374 RESISTOR METAL FILM 15K 0 RESISTOR METAL FILM 15K 0 1 0 1W 25PPM 0805 TAPE 0 1W 25PPM 0805 TAPE 1274218 R64 65 RESISTOR A52R RES CF 560K 5 0 5W 640364 Cram 92 RESISTOR A73R RES CERM 10K RESISTOR A73R RES CERM 10K 5 2W 100PPM 2W 100PPM 650405 EE List of Replaceable Parts 5 Parts Lists Table 5 3 A3 Motherboard PCA cont Ref Part Des Description Number Qty R89 90 RESISTOR RO5A RES CF 1 5 0 25W 867866 RESISTOR A73R RES CERM 560 5 2W 100PPM 643764 R124 125 125 RESISTOR SMR RES CERM 86 6 RESISTOR SMR RES CERM 86 6 1 0 1W 100PPM 0805 0 1W 100PPM 0805 106929
61. au u n er AC Current Operation Thermocouple Temperature Measurement Iso thermal Block Reference Junction Temperature Measurement Thermocouple Voltage Measurement Thermocouple Temperature Simulation esee Analog to Digital Converter Fault Detection erret titor deo euer EE Digital AT Current PCA m 291 2 1 2 2 57LFC AN Service Manual Detailed Hardware Description of DC AC Current Low Current Output Mid Current Output Amplifier essere High Current Output Amplifier High Current Amplifier Power Supplies Mongo Supplies 8 High Voltage Detailed Hardware Description of the 22 V Amplifier Detailed Description of the 220 V Amplifier Detailed Hardware Description of the High Voltage Regulator Heat Sink Temperature Measurement Digital Interface and A9 Out Guard CPU PCA Real Time Clock IEEE 488 Interface Theory of Operation 2 Introduction Introduction This Chapter is intended to provid
62. relay U45 will turn on and normal bias current will be provided by R63 The high current power supply is located on the A3 Motherboard PCA and is composed of U23 U24 Q14 Q17 Q9 C87 C53 and associated components The AC input voltage from the main power transformer is full wave rectified by CR64 and CR60 for the positive supply and by CR65 and CR61 for the negative supply When transistor Q14 is on the positive rectified voltage will charge C87 which provides MMONGO output 014 is controlled by U23 The inputs to 023 are IREF on the input and the full wave rectified AC on the negative input If the IREF signal is larger than the AC input signal the open collector output of U23 will be off and the gate 2 43 57LFC AN Service Manual of Q14 will be biased on by 151 supply through R70 and R74 Once 014 is on it will remain on until C87 is charged up to a voltage equal the IREF signal and then Q14 will be turned off by U23 The voltage at the negative input of U23 turns on the output and shorts the input voltage to Q14 If Q14 is off diode CR47 which 15 connected between the negative input of U23 and the supply output will begin to conduct when the AC input 15 one diode drop greater than the supply output If the supply output decreases more than one diode drop from the IREF U23 will turn off and turn Q14 on and allow C87 to charge for more of AC input cycle rather then waiting for the next cyc
63. x don t care H High Off L Low On 2 9 57LFC AN Service Manual 2 10 LED Control and Output Cables Sheet 5 of the schematic shows the LED control panel LED s connector The LEDs are mounted on their own daughter card with control wires cabled from the A3 Motherboard PCA A description of each LED is provided in Table 2 5 Table 2 5 Functional Description of LED Signals Signal Functional Description STANDBY Turns on the STANDBY LED when asserted Low YELLOW OPERATE Turns on the OPERATE LED when asserted Low GREEN WARNING Turns on the WARNING LED when asserted Low RED CKHVCUR Turns on an analog switch to place the rectified and filtered shunt voltage generated by the HVCOM current onto the SMUX line when asserted Low CKIT Turns on a switch to connect the output of the temperature to SMUX Sheet 1 of the A3 Motherboard PCA schematic shows the connection and wiring for the output cable from the A3 Motherboard PCA to the front panel binding posts Note that there are two guards IGUARD and GUARD voltage guard These guards may be tied together through K8 when voltage is selected The other signal leads are OUT HI SNS HI OUT LO and SNS LO The output high and low signals OUT HI and OUT are used for the main output for volts current and ohms The output sense signals SNS HI and SNS LO are used to sense and internally adjust the output signals The sense terminals are n
64. 07 8 TRANSISTOR SI NPN 2N3904 60V 200MA 300MHZ 625MW AMMO 698225 TO 92 TAPE 12 TRANSISTOR SI NPN 300V 1W TO 92 SI NPN 300V 1W TO 92 722934 Q13 TRANSISTOR SI PNP 2N5401 160V 600MA 100MHZ 350MW AMMO 698274 PNEU 92 Qs TRANSISTOR SI PNP 2N6520 350V 500MA 40MHZ 625MW TO 92 TAPE_ SI PNP 2N6520 350V 500MA 40MHZ 625MW TO 92 TAPE 602961 1 THYRISTOR SI TRIAC VBO 200V 8 0A 413013 EN R1 2R9 RESISTOR SMR RES CERM 2K 1 125W 100PPM 1206 807172 11 R12 R14 17 R26 R66 67 R RESISTOR SMR RES CERM 32 4 1 0 1W 100PPM 0805 641974 R7 R13 RESISTOR SMR RES CERM 1K 1 125W 100PPM 1206 783241 7 R30 R60 R62 R71 R75 R5 R8 RESISTOR SMR RES CERM 10 1 125W 100PPM 1206 867676 R11 R32 RESISTOR SMR RES CERM 4 99K 1 125W 100PPM 1206 604345 13 R53 R58 R69 R79 82 R87 R109 110 Ert 13 R18 19 19 RESISTOR SMR RES CERM 1K 596 1W 200PPM 2512 601176 R20 R27 RESISTOR CERMET 100 1 0 125W 100PPM 1206 TAPE 867494 R111 57LFC AN Service Manual 5 14 Table 5 3 A3 Motherboard PCA cont Ref Part Des Description Number Qty R21 R23 RESISTOR SMR RES CERM 49 9K 1 125W 100PPM 1206 836379 R28 R116 RESISTOR SMR RES CERM 453 1 125W 100PPM 1206 801415 R24 R115 RESISTOR CERMET 150K 1 0 125W 100PPM 1206 TAPE 867697 2 R25 R29 RESISTOR 5 5 100 190 125 100 1206 769802 R33 R78 R83 85
65. 1 125W 100PPM 1206 867676 57LFC AN Service Manual 5 20 Table 5 4 A5 Ohms PCA cont Ref Part Des Description Number Qty R10 12 RESISTOR SMR RES CERM 10K 1 125W 100PPM 1206 769794 R16 R23 RESISTOR SMR RES CERM 4 99K 1 125W 100PPM 1206 604345 RESISTOR SMR RES MF 10K 0 596 125W 10PPM 1206 687407 40 41 RESISTOR SMR RES CERM 2K 1 125W 100PPM 1206 807172 R54 55 RESISTOR SMR RES CERM 24 9K 1 125W 100PPM 1206 867689 R56 57 RESISTOR SMR RES CERM 100K 196 125W 100PPM 1206 769802 R6 R58 61 RESISTOR SMR RES CERM 15K 196 125W 100PPM 1206 769810 POWER TRANSFORMER 16 5V 17VCT 625977 CONNECTOR TERMINAL TEST 1510 602125 TP10 4 028 032 OHMS SPST QUAD NC LOW LEAKAGE SO16 TAPE 3 026 27 BIPOLAR AD707K SMR IC OPAMP ULOW DRIFT LOW NOISE SO8 887120 U31 OFFSET 1MHZ DIFET SO8 TAPE 4 5 6 0 1 04 AMP AD825 5V 15V 2MV 2115379 04 OFFSET 18MHZ JFET SO8 TAPE BIPOLAR 4040 SMR IC V REF SHUNT 2 5 V 1 150 PPM SOT23 930065 List of Replaceable Parts 5 Parts Lists Table 5 4 A5 Ohms PCA cont Ref Part Des Description Number Qty VR3 4 ZENER UNCOMP MMBZ5233B 6V 596 20MA 225MW SOT 23 TAPE 837161 THIN FILM HERM RESISTANCE REF 2063764 5 21 57LFC AN Service Manual 5 22 CAUTION SUBJECT TO DAMAGE BY STATIC ELECTRICITY
66. 1206 TAPE 2113695 2 R261 R277 RESISTOR CERMET 10M 1 0 1W 400PPM 0805 TAPE 943659 2 R278 RT001 THERMISTOR DISC POS 47 20 25C 604139 2 RT002 WIRE JUMPER TEF 22AWG WHT 200 529776 5 50 List of Replaceable Parts 5 Parts Lists Table 5 7 A8 High Voltage PCA cont Ref Part Des Description Number Qty CONNECTOR TERMINAL TEST POINT 1510 TAPE 602125 U1U2 LF353 SMR IC OP AMP DUAL JFET INPUT SO8 688579 ER IC OP AMP OPA637 4 5V TO 18V 250UV OFFSET 80MHZ HI 2091008 SPEED DIFET SO8 TAPE 17 reme 1 mmm U9 BIPOLARLM393 SMR IC COMPARATOR DUAL LOW PWR SOIC BIPOLAR LM393 SMR IC COMPARATOR DUAL LOW PWR SOIC p IC ANALOG SWITCH DG413 3 44V 35 1563433 OHMS SPST QUAD 2NC 2NO SO16 TAPE U12 BIMOS 5800 SMR IC BIMOS 4 CHNL DRVR W LTCH SOIC 929781 U13 U14 CMOS 74HC374 SMR IC CMOS OCTAL D F F EDG TRG SOIC 866798 2 U17 U15 AMP OP196 3 12V 300UV OFFSET 350KHZ R R S S SO8 TAPE 2101052 2 U16 U19 IC ANALOG SWITCH DG408 15V 100 OHMS 8 1 2101034 1 MULTIPLEXER SO16 TAPE ue AMP AD744J 4 5 TO 18V 2MV OFFSET 6MHZ HI SLEW 929992 2 RATE SO8 TAPE 5 51 57LFC AN Service Manual Table 5 7 A8 High Voltage PCA cont Part Description Number Qty E IC VOLTAGE REFERENCE ZRB500 5V 196 50PPM C 150UA SOT 2101029 23 TAPE ZENER UNCOMP MMSZ5240B 10V 596 20MA 500MW SOD 123 TAPE 2060235
67. 1W 100PPM 0805 TAPE RESISTOR SMR RES CERM 4 99K 1 125W 100PPM 1206 RESISTOR SMR RES CERM 4 32K 1 063W 100PPM 0603 5 27 57LFC AN Service Manual 5 28 Table 5 5 A6 Digital Synthesis PCA cont 99 RESISTOR SMR RES CERM 49 9K RESISTOR SMR RES CERM 49 9K 1 125W 100PPM 1206 125W 100PPM 1206 836379 4 R100 RESISTOR SMR RES CERM 4 99K 1 0 1W 100PPM 0805 928767 E R103 R104 RESISTOR SMR RES CERM 49 9 1 0 1W 100PPM 0805 604923 R107 RESISTOR SMR RES CERM 1M 5 063W 200PPM 0603 604998 RESISTOR SMR RES CERM 10K 1 0 1W 100PPM 0805 928791 R146 RESISTOR SMR RES CERM 1 8K 5 125W 200PPM 1206 746453 R159 RESISTOR SMR RES CERM 6 98K 1 125W 100PPM 1206 929919 CN R186 RESISTOR SMR RES CERM 301 1 125W 100PPM 1206 644598 27 RESISTOR SMR RES CERM 49 9 1 0 25W 100PPM 1210 929674 THERMISTOR SMR THERMISTOR 3 25 8055 642519 EMI POWER TRANSFORMER 16 5V 43 6VCT 627031 EA TP2 4 CONNECTOR TERMINAL TEST POINT 1510 TAPE 602125 16 TP6 10 TP18 25 BIMOS 5800 SMR IC BIMOS 4 CHNL DRVR W LTCH SOIC 929781 07 013 IC OP AMP AD744J 4 5 18V 2MV OFFSET 6MHZ HI SLEW 929992 5 017 029 8 U32 010 023 IC ANALOG SWITCH DG444 12 TO 20 85 875232 U25 26 OHMS SPST QUAD NC SO16 TAPE U28 U47 BIFET LF412A IC OP AMP DUAL LO OFFST VOLT LO DRIFT 851704 BIPOLAR OP27G SMR IC OP AMP ULOW NOISE LOW VOS SO8 68
68. 2 MP9 MP7 HEATSINK ASSEMBLY 2117192 2 MP11 MP15 EJECTOR PWB NYLON 494724 MP16 CONNECTOR CONN DIN41612 TYPE C RT ANG 64 PIN 807800 P28 NPN MMBT3904 SMR TRANSISTOR SI NPN 60V 350MW SOT 23 742676 TRANSISTOR SI PNP 150V 300MW TO 92 266619 TRANSISTOR SI NPN 2N5551 180V 600MA 100MHZ 625MW TO 1791849 92 TRANSISTOR SI PNP MJD350 300V 500MA 1 56W D PAK TAPE 2063630 TRANSISTOR SI PNP MMBT3906 40V 200MA 250MHZ 225MW SOT 742684 10 23 TAPE 5 43 57LFC AN Service Manual Table 5 7 A8 High Voltage PCA cont Ref Part Des Description Number Qty TRANSISTOR SI NPN MJD340 300V 500MA 1 56W D PAK TAPE 2063627 FET DMOS N CH ROSA TRANSISTOR SI N DMOS 500V TO 92 782490 MOSFET P CHN RO5A TRANSISTOR SI P MOS 500V TO 92 782508 E TRANSISTOR SI PNP 2N6520 350V 500MA 40MHZ 625MW TO 92 TAPE 602961 TRANSISTOR SI NPN 350V 625MW TO 92 TRANSISTOR SI NPN 2N3904 60V 200MA 300MHZ 625MW 92 R1R2 RESISTOR SMR RES CERM 470 596 125W 200PPM 1206 740506 4 R102 R111 R3 R9 RESISTOR SMR RES CERM 27 596 125W 200PPM 1206 807735 R4 R6 RESISTOR CERMET 10 5 0 25W 200PPM 1206 TAPE 2060987 u R8 R10 R5 R7 RESISTOR SMR RES CERM 22 596 125W 200PPM 1206 746230 5 44 List of Replaceable Parts 5 Parts Lists Table 5 7 A8 High Voltage PCA cont Ref Part Des Description Number Qty RESISTOR SMR RES CERM 1K 1 0 1W 100PPM 0805 928713 RESISTOR C
69. 2 2 A3 Motherboard Power up and Fault Relay States 2 8 57LFC AN Service Manual Table 2 3 A3 Motherboard PCA Final Relay States by Instrument State Virtual EC MBRLY wee per es e e EIE Weight a SUS 03ad Eu Guard mod 0000 0000 r T 0010h Internal Sense e cei 0000 0000 EET EO Sense 0002 0002 22 A6 Output ee Standby 22 mV A6 03ad Trema 220 mV A6 Output 02 4 Standby 220 mV A6 r 03ad Output Optt 3 3 V A6 Output 03a0 0360 03a2 03a2 F LO Comp Amp Opt 3 3 Output 0210 0260 0262 Standby Opt 3 3 r s s s r s r r 03ad Output 2 2 V Buffer Out using LO 0380 0390 0382 0392 Amp PUT 2 2 V Buffer 038d Output 22 V A8 Output using LO 03a0 03b0 03a2 03b2 T T Amp SEE 220 V A8 Output Using 03e8 03f8 03ea O3fa LO Comp Amp 220 Output 0218 o2ea o2fa CR 5 Output Wie s Lor Seray ormsasan v s s Ta Ts oza o Standby onmsas2w s s PIRINI Se as comp s 0894 oma oss a Current A7 Current Output sumar
70. 2 and verify the Calibrator 15 within the limits shown in Table 3 3 FLUKE 57LFC 57i Fc system 8508A INPUT SENSE FLUKE 2 WIRE A 4WIREQ ACV 1420 PK MAX 1000 00000000 2 005 Figure 3 2 8508A Connections to the 57LFC for AC Volts Measurement 57LFC AN Service Manual Table 3 3 AC Volts Measurement Limits Upper Limit Lower Limit Range Amplitude Frequency Reading V V mes _ zemees mss e roos aes raro faes arses mes m nares mes mes e renes nest soca mors aooo fae __ em e em mee nsus _ em sees oo fe fa e nuns a fe p emm m fa m ms zem ms wes aoee numen Lm fe e nessun 2 m e Lm fe Lm m eme nes m we Frequency Accur
71. Current PCA 5 38 List of Replaceable Parts 5 Parts Lists Table 5 7 A8 High Voltage PCA Part Number 10 ISOIHERMALPCA C1 C2 CAPACITOR SMR CAP CER 0 1UF 10 100V X7R 1206 804325 ES C8 C34 CAPACITOR SMR CAP CER 0 1UF 10 50V X7R 0805 690500 5 39 57LFC AN Service Manual Table 5 7 A8 High Voltage PCA cont Part Description Number Qty CAPACITOR CAP AL 3 3UF 30 20 450V 782524 C9 C35 CAPACITOR CAP AL 10UF 20 160V SOLV PROOF 817064 C14 CAPACITOR SMR CAP CER 100PF 5 50V COG 0805 514133 C42 C61 CAPACITOR FILM POLYESTER 1 0UF 10 50V 7360 TAPE 2063474 C92 CAPACITOR SMR CAP TA 100UF 20 10V 7343 929877 C44 CAPACITOR CAP CER 0 02UF 20 500V Z5U 407403 C25 C18 CAPACITOR CERAMIC 22PF 5 1000V C0G 1808 TAPE 2062822 C24 C45 CAPACITOR FILM POLYPHENYLENE SULFIDE 0 22UF 1546405 C19 4 C46 20 50V 7360 TAPE C47 807610 CAPACITOR SMR CAP POLYES 0 47UF 10 50V 7360 802519 CAPACITOR SMR CAP CER 10PF 5 50V COG 0805 494781 CAPACITOR SMR CAP CER 470PF 1 50V COG 0805 929476 CAPACITOR SMR CAP CER 47PF 5 50V COG 0805 494633 4 C 82 C48 CAPACITOR CERAMIC 10PF 2 1000V COG 1808 TAPE 1579905 1 1 5 40 List of Replaceable Parts 5 Parts Lists Table 5 7 A8 High Voltage PCA cont Ref Part Des Description Number Qty CAPACITOR SMR CAP TA 1UF 20 35V 3528 866970 CAPACITOR SMR CAP CER 22PF 1
72. EXT LO COMP OUT LO AN AMAN AM R11 10 0K U17 AAA COMP RES LO 185 LTC1151C 1 00 1 00K COMP CIRCUITRY FLOATING POWER SUPPLY Q2 3 75V WITH RESPECT TO FCOM FLOATP MPS6560 SEL CR4 DB101S C68 1 C67 1 10000 10000 10000 1 TE 5520A 6503 MPS6562 57LFC 1005 2 of 5 8 7 6 5 4 3 2 Figure 6 3 A5 Ohms PCA cont 6 13 57LFC Service Manual 485 CD INIVREF aN c20 RCOM2 4 C59 0 1U lt 15V 485 E ZIVREF ISELGRD 45V 15V C33 45V 15V 28 29 VL V U22 ADG444 1 45V 15V C24 25 VL V U21 3 D aN GND V in C32 TO72 R27 10 0K 0 5 10 PPM C 485 8 20 1 6 7 3 R28 ENCOMPFAULT C58 104 5V 15V YF m 0 10 R49 AWN IND 10 3775V 7 022 ADG444 ADG444
73. Maximum compliance voltage is 4 V in 2 2 A range and 10 V on other ranges FLUKE 57LFC 57 Fc system INPUT SENSE 8508A AEFERENCE MULTIMETER 2 WIRE A 4 0 ACV inn FE T mU Fas ino 3 apv009f eps Figure 3 6 8508A Connections to the 57LFC for DC Current Measurement Table 3 7 DC Current Readings ______ mes omen _ sme ames omem memes omen mes mes mes 2 em ______ 2 s 2 fee eem Calibration and Verification 3 Verification Tests AC Current Test The ac current amplitude accuracy test verifies the accuracy of AC Current at the Calibrator output terminals First use the 5720A to characterize all the points in Table 3 8 Next connect the equipment as shown in Figure 3 7 and verify the Calibrator is within the limits shown in Table 3 8 Maximum compliance voltage is 4 V in 2 2 A range and 7 V on other ranges FLUKE
74. R82 10 0K MMBT3906 933 4 99K 4 19 823 RFP70N3 U24 TO220HS 2 2 4 LM393DT TP16 151 100MIL IREF 7 SHIELD ISHLD CR21 RT11 CR39 GF1G 7936 CR20 TP20 180M 0 10 2 151COM I 151 UNR 1 GF1G 151 T 50MIL 50MIL RT12 C103 1015 1 T15IAC2 0 1U 1 L 56 L CR90 3300U 0 1U 10U MBRS140 3 5 35v TO220HS 25V TP18 TP19 50MIL 180M 50MIL 196 50MIL 5 coo 55 TO220HS CR89 5 aan 0 20 E SESS TP17 1 151 UNR 15I 50MIL GFiG R11 AMV 4 99K 15V C14 10 15V 2N3904 CR5 A cric CR4 BAV199 Q7 2N3904 MMBT3904 15V Q6 MMBT3906 TP1 V3BUF 4 N AWN 10 0 1 00K Q5 MMBT3904 MMBT3906 02 2N3906 CR3 Q1 A Gric 2N3906 15V 57LFC 1003 4 of 5 Schematic Diagrams 1 2 Figure 6 2 A3 Motherboard PCA cont 6 9 57LFC Service Manual 8 7 6 5 4 3 1
75. S 1 1 5 5 5 1 5 1 1 1 1 S 5 5 x 15 IM 6L 4 4 4 4 5 5 4 5 5 5 5 4 5 5 5 4 5 4 5 5 5 5 5 4 4 5 5 4 5 5 5 x M 6L 1 S S S 4 5 4 5 1 S S 1 S S S S S 1 1 S 1 S S 5 5 x AGLS M OY OL 1 1 1 1 S S 1 S S s s 1 s s 1 S S 1 5 5 5 5 5 1 1 5 1 5 5 5 5 X M 0L 1 4 4 1 S S 1 S S S S 1 S 1 S S S 1 S S S S S 4 S 1 5 5 1 x M OX6L 7s r 8 S 4 amp vM 8 9 6 6 0 2 2 0 4 0 9 91 S v za za ta em 17 4 DELL amp O4 za 20 6 27 97 27 DI D9 _ A1HO 2 22 2 S Q S o Q 5 lt gt 2 Table 2 9 Final Relay States by Instrument State cont 5 5 1 5 11 1 5 1 5 5 5 5 5 15 1 5 5 815 MZ O 01 a 1 8 8 sis 8 0401 8 585 5 8 1 8 8 s 8 1 5 A81S 6L 8 5 1 15815 0461 15618 2 68 2 2 5 1 8 8 8
76. TP6 TP24 TP25 22 csi R53 R49 5 ors 88 Thre R 6 cores C3c27 2n 2 74 sc wi4 2 WLS R790 m wa E J 012 25 oa Fh EDS EIS a Tn R86L1 J 56548 C49 C BSS 659 13700 854 R950 2208 106 1 185 o e C29 135 8 c 0 8163 sap BH Os 08 rail 4 E trip B 5 10702 1 108 nc C61 R119 C100 C109 5 H CR29 5 O a CAUTION SUBJECT TO DAMAGE BY STATIC ELECTRICITY 2 1 57LFC 7607 6 26 Figure 6 5 A7 Current PCA Schematic Diagrams
77. YELLOW 083 STANDBY HMPL 1503 DS2 HLMP 1401 6 4 Figure 6 1 A1 LED cont 57LFC 1001 l B epo BA OF 08 5 melma Bar 5 1191118 rm 44 rr MIEL R11 69 s 0 5 888 20 05 BBBB LI 88 BERE cs 514 BE B BB 5 Sm RBG Clea CR38 CR39 CR37 TP36 C115 5106 TOP VIEW CKT 6 42 1 1844 R430 4 5 21 L R98 104 109 CR74 CR78 3 75 TP43 cneo 3 CAUTION SUBJECT TO DAMAGE BY STATIC ELECTRICITY Schematic Diagrams 6 D H1 16 RIVETS FOR DIN CONECTORS C B 57LFC 7603 2 Figure 6 2 A3 Motherboard P
78. between the buttons and the transistor as possible The thermistor is biased with a programmable current sink via TC ISO SRC This current sink consists of U97 U6 R108 R126 and R127 and provides about 10 developing about 1 V across the thermistor The voltage of the themistor is measured by connecting TC ISO to the A D input with U82A Thermocouple Voltage Measurement The thermocouple voltage is multiplied by 10 on the A10 Isothermal PCA It is then switched into the A D by U82 The A7A10 Isothermal PCA is assembled and tested as part of the A7 Current PCA Thermocouple Temperature Simulation that is required to simulate a thermocouple 15 source a voltage that would be generated by a thermocouple at that temperature The reference junction is measured to determine the temperature of the isothermal block Then this temperature and the requested temperature are used to determine the correct output voltage This voltage is generated by the 3 3 DC range buffered by U13 and divided by 10 on the A10 Isothermal PCA before being outputted on the thermocouple connector Analog to Digital Converter Refer to Sheet 4 on the A6 Digital Synthesis PCA schematic All internal calibration and diagnostic measurements are buffered by a gain programmable instrumentation amplifier U10 The gain of this amplifier is selected by closing U82D X10 closing U82C 40 or by leaving both open X1 The output of 010 is applied to the A D 030 wher
79. deu E MEEL SES MA rm 5 5 Digital Synthesis 5 23 57LFC AN Service Manual AT Current PCA gt High Voltage 8 AQ Out Guiard CPU PCA a 5 6 5 7 5 yi 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Q QQ OQ Q tata ta ta Q Q Cn Q C2 Q Q C CJ CJ Q Q C2 CINA OU purs Qo qu u CA parui Ac e List of Figures S7LEC Block Rer or e dept ee Pre 2 41 Block Diagram of the 5 Ohms 1 40121 2 410 430 000000000011000 0080554 AS Ohms High Low AS Ohms High Low Current Functions o entere ceded HT HERE EHE EIER AC Current Functions 8 High Voltage PCA 22 V and 220 V Amplifier 24 8508A Connections to the 57LFC for DC Volts Measurement 3 7 8508A Connections to the 57LFC for AC Volts Measurement 8508A Connections to the 57LFC for AC Frequency Measurement 8508A Connections to the 57LFC for 4 Wire Ohnss 8508A Connections to the 57LFC for 2 Wire Compensated Ohms 8508A Connections to the 57LFC for DC Current Measurement
80. is similar to the 15 V BALANCE FAULT and monitors that 45 V and 45 V supplies stay within a fixed range of each other Table 2 6 A3 Motherboard PCA Test Points List jeu eo pow we pev emo we me ww pec peo mme oo Theory of Operation A5 Ohms PCA Table 2 6 A3 Motherboard PCA Test Points List cont pem pe ms we me we me eum m pue me jew me ewe me jw me puw me po ems List of Fuses There are several fuses used on the A3 Motherboard PCA when resistive thermal switches cannot be used The fuses are used primarily in the high voltage power supply circuits and F2 are used to protect the raw 45 V supplies F4 and F5 protect the 180 V supplies and F3 and F6 protect the 360 V supplies A5 Ohms PCA The following discussion covers the theory of operations for the A5 Ohms PCA circuitry The A5 Ohms sources 1x and 1 9x fixed value resistances provides compensation and generates an active guard The A5 Ohms can source ohms in one of several ways two wire two wire with compensation and four wire ohms For discussion purposes the A5 Ohms PCA can be divided into several areas precision thin film resistor networks relay switch matrix and control circuits other control circuits guard circuit two wire compensation circ
81. may cause the ZGUARD buffer to cause errors in resistance measurement Note that the resistors have maximum peak currents that should not be exceeded and excessive current for extended periods of time may damage the resistors and create a long term offset Only one resistor is switched onto the out high and out low signal traces at a time The output and sense resistor traces are directed to the output terminals through a series of relays Relay Switch Matrix and Control 2 14 The relay switch matrix and resistors are shown on Sheet 1 ofthe A5 Ohms PCA schematic and the switch control circuits are shown on Sheet 5 of the AS Ohms PCA schematic A block diagram of the high low and high sense low sense relay routing is shown in Figures 2 2 and 2 3 The relay matrix provides switching between the various resistor values and the A3 Motherboard PCA and also switches in guard circuits 2 wire mode compensation circuits and other compensation circuits These relays are latching type and can be set or reset A3 Motherboard PCA connections are shown on Sheet 1 8A 8D K29 and K30 isolate the ohms output and sense lines from the A3 Motherboard PCA The HIGUARD signal is switched through K25 and can be used to drive the shields of HI cables when the Calibrator output 1s active See the Guard Circuits section for more details Theory of Operation A5 Ohms PCA NL Comp Out Lo K31 apv002 eps Figure
82. occur if a diode bridge on Sheet 3 of the A3 Motherboard PCA schematic or other components short Theory of Operation Motherboard The 45 ac 180 ac and 360 ac provide the raw voltages that will be used by the A8 High Voltage and A5 Ohms PCAs If secondary voltages become too large TRIAC 019 will turn on the limit voltage open the mains fuse and prevent damage CR62 is the full wave rectifier for the 45UNR supply The 45UNR are regulated to become the 45V supplies MP7 and MP8 are assemblies that contain the heat sinks and the main pairs of drive transistors for the 45 V regulated supplies U18 controls the regulation Q12 with resistor R48 and R54 and Q13 with resistors R49 and R57 limit the output currents to 120 mA CR28 with VR10 and VR11 and CR 26 with VR12 and VR 13 protect against high voltages damaging the regulation circuits Note that the HVCOM line caries the ground return currents for the high voltage supplies back to the center tap of the transformer On Sheet 3 of the A3 Motherboard PCA schematic CR67 and CR51 rectify the 15 V ac and 5 V ac left side of the Sheet respectively The resulting 15UNR goes through U21 a dual regulator and becomes the guarded 15 V supply 15UNR goes into U22 and becomes the 15 V supply VR14 and 15 limit short term over voltages to 22 V or so The 5 ac signals are regulated to be the power for the relays 5RLH and the logic 5 V The 15 V supplies are referenced
83. on the 220 range Transistors Q41 Q42 and resistor R7 limit the current that could be forced back into the circuit if a voltage is applied to the output terminals of the instrument when the low current amplifier is in use The current will be limited to between 10 mA and 50 mA with transient voltages up to 350 V Solid state relay U34 is used to disable the amplifier when it is not being used A high on the LO CURRENT DISABLE line from the digital control circuit will turn on the relay shut off the bias current in the amplifier and put it in a dormant state The transconductance of this current amplifier is 2 mA V on the 2 2 mA range and 214 V on the 220 range Mid Current Output Amplifier The output amplifier for the 22 mA and 220 mA ranges is composed of U7 U58 U31 Q3 Q5 014 015 MP13 MP14 and associated components This amplifier uses the T common for its ground reference This is a class A push pull output stage amplifier with 242 mA bias on the 220 mA range and 27 mA bias on the 22 mA range and 14 supply the positive output current MP14 and 015 supply the negative output current Relay K2 switches in the resistors to set the bias current With the 1 ohm resistors switched in to emitters of MP13 and 14 the bias will be set at 242 mA With the 10 ohm resistors switched in the bias will be 27 mA Input pin 6 of U31 connects to the emitter resistors of MP13 and input pin 5 of U31 c
84. then out of RAM The real time clock provides the calendar functions for the instrument If the real time lock battery wears out when power off the instrument will lose its ability to keep track of the calibration cycle See Sheet 2 of the A9 Out Guard CPU PCA schematic IEEE 488 Interface 2 52 The TMS9914 IEEE 488 IC is used for all remote IEEE 488 communication There are two buffers that provide the correct driver capability for the IEEE 488 bus In general the product complies will all parts of the IEEE 488 standard Note that 012 and U19 not installed See Sheet 3 of the A9 Out Guard CPU PCA schematic RUN Chapter 3 Calibration and Verification Title Page Instruction Step INS 3 4 Reference Step REE uuu rte re eee e e e nes 3 4 NOT Verification Tests Test Equipment Calibrator Configuration and Pre check DC Voltage Testa 3 7 Voltage Tests IDE 3 9 AC Voltage Accuracy Test 5 9 Frequency DC Current Test AC Current Test wipe GM MOM Current Output Compliance Voltage Output Compliance Harmonic Test Levels for AC Harmonic AC Current Test a asas eene External Trigger Verification Test Check 5 3 1 57LFC AN Service Manual 3 2 Calibration and Verification 3 Calibration Calibration Calibration of
85. to SCOM while the 5 V supplies are referenced to DCOM Note that SCOM and DCOM grounds are kept close to each other electrically due to the Schottky diodes CR18 and CR19 CR29 and CR31 limit the amount that the 15 V and 5 V power supplies can float from each other Each regulator in the design is protected against short term over voltages occurring at the regulator output with diodes CR41 CR48 CR35 CR36 and CR34 The 6 turn beads reduce conducted noise Outguard Power Supplies The connector P1 and the out guard secondaries labeled 12GAC and 5GAC are shown on Sheet 2 of the A3 Motherboard PCA schematic These unregulated supplies including 5 become the regulated supplies for the outguard controller card A9 and include 5VG and 12VG These supply power the A9 Out Guard CPU PCA through the connector J1 found on Sheet five RT1 and RT3 RTS protect the transformer from large current draws that might occur if there is a short down stream Each regulator in the design U20 U25 and U19 is protected against short term over voltages occurring at the regulator output with diodes CR42 CR43 and 59 The 6 turn beads reduce conducted noise The regulated 12 V supplies also provide power to the 24 V fan located at the front of the instrument A second fan connector was added for a future version of the instrument GCOM is the reference and is tied through resistors to earth and tied to DCOM the in guard digital groun
86. voltage The signal at the drain of Q33 is then fed to complimentary Darlington emitter follower output transistors Q45 Q27 and 046 044 The output stage bias current is set by the quiescent voltage imposed across the series parallel combination of resistors R186 to R189 this voltage is the collector emitter voltage of Vbe multiplier transistor Q49 less the base emitter voltages of Q27 Q44 Q45 and Q46 Resistors R186 to R189 in conjunction with resistors R195 R196 and variable resistor R197 are chosen to allow this current to be set at 18 mA High voltage N channel mosfet devices Q1 and Q25 isolate Q27 and Q45 from the high potentials necessary to obtain the specified Amplifier output voltage swing The collector emitter voltage of Q27 and Q45 is set at approximately 12 V by Zener diode VRIS5 which is referenced to the amplifier output and gate source voltage of Q1 Bias current for VR15 is supplied by series parallel resistor combination R95 R96 R98 to R101 R103 and R104 which also serves to set the gate voltage of 025 at approximately half way between the PA supply and amplifier output voltages the voltage presented across Q1 and Q25 is thus shared equally between the two devices C18 is included to counteract the effect of input capacitance of Q25 thus ensuring effective voltage sharing up to the maximum operating frequency High voltage P channel mosfet devices Q2 and Q29 isolate Q44 and Q46 in a similar manner Because the volta
87. will submit an estimate of the cost to repair shipment damage Fluke will be happy to answer all questions to enhance the use of this instrument Please address your requests or correspondence to Fluke Corporation P O Box 9090 Everett WA 98206 9090 Interference Information This equipment generates and uses radio frequency energy and if not installed and used in strict accordance with the manufacturer s instructions may cause interference to radio and television reception It has been type tested and found to comply with the limits for a Class A computing device in accordance with the specifications in Subpart J of Part 15 of FCC Rules which are designed to provide reasonable protection against such interference in a residential installation However there is no guarantee that interference will not occur in a particular installation If this equipment does cause interference to radio or television reception which can be determined by turning the equipment off and on the user is encouraged to try to correct the interference by one of more of the following measures e Reorient the receiving antenna e Relocate the equipment with respect to the receiver e Move the equipment away from the receiver e Plug the equipment into a different outlet so that the computer and receiver are on different branch circuits If necessary the user should consult the dealer or an experienced radio television technician for additional suggestions The user
88. 0 CAPACITOR SMR CAP CER 3900PF 590 25V C0G 0805 690560 C129 CAPACITOR SMR CAP CER 0 047UF 20 50V X7R 1206 782615 2 130 C131 CAPACITOR SMR CAP CER 10PF 1096 50V C0G 1206 747311 ctas CAPACITOR SMR CAP CER 0 033UF CAPACITOR SMR CAP CER 0 033UF 10 200V X7R 1206 200 7 1206 602547 1 10 DIODE SI PN MMBD1503A 150V 200MA DUAL SERIES LOW 928143 LEAKAGE SOT 23 TAPE CR11 DIODE 2MA 1090 7 686714 DIODE SI 100V 1A DO 214 912451 CR17 DIODE SI PN DF01S 100V 1A BRIDGE 4 PIN SURFACE 912456 CR26 MOUNT 3530 TAPE CR27 DIODE SI SCHOTTKY 40V 1A DO 214AB 605821 28 CR29 DIODE SI SCHOTTKY BAT54S 30V 200MA 5NS DUAL SERIES SOT 929745 2 30 23 TAPE List of Replaceable Parts 5 Parts Lists Table 5 6 A7 Current PCA cont Ref Part Des Description Number Qty SURGE PROTECTOR 90V 20 198507 H12 15 RIVET AL 089 DIA 344 L SEMI TUBULAR OVAL HEAD 838458 K1 2 K5 RELAY ARMATURE 2 FORM C 5 VDC LATCH 910773 d Dus HEAT ASSEMBLY WH WENO STR HEAT SINK ASSEMBLY WITH MJE15028XSTR SINK ASSEMBLY WITH MJE15028 XSTR 2062797 1 P107 CONNECTOR DIN41612 TYPE C RT ANG 64 PIN 807800 TRANSISTOR SI PNP 80V 10W TO 202 SI PNP 80V 10W TO 202 495689 as E 06 TRANSISTOR SI PNP MMBT3906 40V 200MA 250MHZ 225MW SOT 742684 23 TAPE TRANSISTOR SI NPN 60V 350MW SOT 23 742676 TRANSISTOR SI NPN 80V 10W TO 202 535468
89. 0010 T 0 10 1 1 8842R 4R GT H 5 d R138 RFAMP 4321 2 470 T 5 4 445K REF AMP 15V SGND MECCA SENSE1 RCOM1 RCOM2 2 57LFC 1006 2 of 8 Figure 6 4 A6 Digital Synthesis PCA cont 6 19 57LFC Service Manual NET SPACING TYPE 1000V 1 25 2 2 25 3 5 00M 16 667K 5520A 2702 C144 NET SPACING TYPE 330V 8 9 10 500K 3 a3 C154 5 6 330V 11 330V 15V D 0 1U sce LOOP POLARITY 13 1024 rmy DIAG 1 MDG444 DCV ACV MDG444 E SMUX 2 bla m DDS1 OUT 11 ee K2 8 7 4 15V 13 4 919 ioe Tuus 1000V SENSE BUFFER ee R168 0 1U CR7 DE 13 MMBD1503 6D6 MDG444 V U48 Q acs 16 MDG444 3 3 VOLT AMPLIFIER 14 15 2 14 P106 gt lg x was 15V MDG444 LA VDIV 74HCU04 042 P106 8 4 L26 A12 220 0HM FER NET SPACING TYPE 1000V 1 20 2 16 15V 15 13 10 AD845K a 8 Ve A Ei 1 MDG444 Ri07 2 43 2K LE 0901050790 8 087 SENSE CURRENT 2 TL 62 ve R60 CANCELLATION AAA SENSE 15V 8 1K 5 BUFFER 1
90. 08 RESISTOR CERMET 200K 1 0 125W 100PPM 1206 TAPE 783258 R9 R28 RESISTOR SMR RES CERM 2 2M 5 125W 200PPM 1206 811778 R156 R10 R87 600202 536 RES RC1206 6 04K 1 25PPM 1760171 RESISTOR SMR RES CERM 270 5 125W 200PPM 1206 746354 R19 20 RESISTOR SMR RES MF 1K 0 1 0 125W 10PPM 1206 929880 4 R52 R155 R23 R32 RESISTOR SMR RES CERM 121 1 063W 100PPM 0603 689122 R24 R34 RESISTOR CERMET 0 060 5 0 5W 100PPM 2010 TAPE 105999 R61 62 List of Replaceable Parts 5 Parts Lists Table 5 5 A6 Digital Synthesis PCA cont Ref Part Des Description Number Qty R26 R54 RESISTOR SMR RES CERM 10K 196 125W 100PPM 1206 769794 21 R56 R69 R93 R102 R137 R143 R163 166 R169 172 R175 176 R193 R197 R199 R35 36 RESISTOR SMR RES CERM 316 1 125W 100PPM 1206 604900 R37 R63 RESISTOR SMR RES CERM 2 61K 1 125W 100PPM 1206 781179 4 R38 R42 RESISTOR SMR RES CERM 698 1 0 1W 100PPM 0805 641156 R80 R95 R44 RESISTOR SMR RES CERM 511 1 125W 100PPM 1206 769869 3 R105 R148 R47 48 RESISTOR SMR RES CERM 110 1 125W 100PPM 1206 644473 5 R74 R77 R198 R49 R53 RESISTOR WIREWOUND 1 0 0 5 1W 50PPM 2515 TAPE 1544336 R50 51 RESISTOR SMR RES CERM 10 1 125W 100PPM 1206 867676 R55 91 RESISTOR SMR RES CERM 4 02K 1 125W 100PPM 1206 783266 92 R101 R114 R118 119 R211 RESISTOR SMR RES CERM 1M 1 125W 100PPM 1206 RESISTOR CERMET 47 5 1 0
91. 0805 List of Replaceable Parts Parts Lists 927814 CAPACITOR SMR CAP CER 4700PF 10 50V X7R 1206 C25 C51 CAPACITOR SMR CAP TA 10UF 2096 25V 6032 C29 CAPACITOR SMR CAP CER 2200PF 5 50V COG 0805 942524 3 C30 CAPACITOR CERAMIC 100PF 596 100V C0G 0805 TAPE 601028 C34 CAPACITOR SMR CAP CER 100PF 1 100V COG 1206 644812 5 5 31 57LFC AN Service Manual 5 32 Table 5 6 A7 Current PCA cont D 038 39 39 CAPACITOR SMR CAP CER 330PF CAPACITOR SMR CAP CER 330PF 5 50V C0G 0805 50V C0G 0805 512038 CAPACITOR SMR CAP CER 1000PF 1 50V COG 1206 867668 E CAPACITOR CERAMIC 10UF 20 10V X5R 1210 TAPE 1589417 C47 48 CERAMIC 560PF 596 50V C0G 0603 TAPE 1555376 CAPACITOR SMR CAP CER 0 47UF 10 16V X7R 0805 690545 C52 53 CAPACITOR SMR CAP TA 4 7UF 1096 20V 3528 605433 C55 56 CAPACITOR SMR CAP CER 1UF 80 2096 25V Y5V 1206 605303 CAPACITOR SMR CAP TA 33UF 2090 16 6032 691151 CAPACITOR SMR CAP CER 56PF CAPACITOR SMR CAP CER 56PF 5 50V C0G 0805 00 50V C0G 0805 887901 EMI C69 C71 CAPACITOR SMR CAP TA 100UF 20 16V 7343 803822 M CAPACITOR ELECTROLYTIC TANTALUM 150 CAPACITOR ELECTROLYTIC TANTALUM 150UF 20 20V 7260 TAPE 20V 7260 TAPE 1279156 102 CEEL CAP AL 470UF 20 35V SOLV PROOF 756700 ES 103 C11
92. 1 CR23 CR26 CR28 29 CR31 CR34 36 CR38 39 CR41 43 CR48 CR50 CR52 59 CR63 CR68 69 CR89 CR92 DIODE SI PN BAV199 70V 215MA 3US DUAL SERIES SOT 23 TAPE 605805 CR45 CR6 11 DIODE SI DUAL 50V 250MA SOT 23 851659 15 CR13 CR15 CR37 CR40 CR44 CR47 CR79 80 CR88 CR18 19 DIODE SI SCHOTTKY 40V 1A DO 214AB 605821 CR24 25 CR33 CR49 CR90 91 5 11 57LFC AN Service Manual 5 12 Table 5 3 A3 Motherboard PCA cont Ref Part Des Description Number Qty CR22 DIODE SI SCHOTTKY 40V 3A DO 204AE 604546 CR27 CR60 61 CR64 65 CR46 DIODE SI PN DF01S 100V 1A BRIDGE 4 PIN SURFACE 912456 3 CR66 67 MOUNT 3530 TAPE CR51 DIODE BRIDGE SI 200V 1 5A 296509 2 CR62 CR70 76 DIODE SI 1KV 1A DO 41 707075 CR78 J205 208 oc K9 11 x L1 10 CHOKE 38 4UH 6TURN 6160A 8002 BULK 320911 PCB MOTHERBOARD 2048831 x List of Replaceable Parts 5 Parts Lists Table 5 3 A3 Motherboard PCA cont __ _ jme or P201 CONNECTOR HEADER 1 ROW 156 ANG LOCKING RAMP 3 2137917 PIN BULK P202 CONNECTOR HEADER 1 ROW 156 ANG LOCKING RAMP 5 2137921 1 PIN BULK Q1 2 TRANSISTOR SI PNP 2N3906 40V 200MA 250MHZ 625MW AMMO 698233 2 BOX TO 92 TAPE Q3 Q6 TRANSISTOR SI PNP MMBT3906 40V 200MA 250MHZ 225MW SOT 742684 os 7 i TAPE 045 5 TRANSISTORSINPN amp OV350MW SOT238 1 NPN 60V 350MW SOT 23 742676
93. 10 O through 100 kO HI source bus to OHMS OUT HI Set Connect 19 Q through 190 HI source bus to OHMS OUT HI Reset Connect 1 Z2 resistance to OHMS SNS HI and 10 Q through 100 source bus Set Disconnect 1 Z2 resistance from Reset Connect 100 Q Z2 resistance to OHMS SNS and 10 Q through 100 HI source bus Set Disconnect 100 Z2 resistance from Reset Connect 10 Z2 resistance to OHMS SNS HI and 10 through 100 HI source bus Set Disconnect 10 Z2 resistance from Reset Connect 1 9 Z2 resistance to 19 O through 190 HI sense and source buses Set Disconnect 1 9 kO Z2 resistance from HI Reset Connect OHMS OUT HI to COMP OUT and OHMS SNS HI to COMP RES HI Set Disconnect OHMS OUT HI from COMP OUT HI and OHMS SNS HI from COMP RES HI Reset Connect 10 Z3 resistance to OHMS and SNS Set Disconnect 10 Z3 resistance from Reset Connect 100 Z3 resistance to OHMS SNS and 10 Q through 100 HI source bus Set Disconnect 100 kO Z3 resistance from HI 57LFC AN Service Manual Table 2 7 Functional Description of A5 Ohms PCA Relays cont Functional Description K15 Reset Connect 19 O through 190 kO HI source bus to HI OHMS HI Set Disconnect 19 through 190 HI source bus from HI OHMS K16 Reset Connect 10 Z3 resistance to OHMS SNS and 10 Q through 100 HI source bus Set Disconne
94. 100 109 0 01U 0 01U 0 01U 0 01U L pe J po L 0 1UF 12V V E10 12V vec I 1 I I I 4 Toss 1 C54 41 C68 1 eso c41 c46 css Ces ES 109 109 0 1UF 0 1UF 0 1UF 0 1UF 0 1UF 0 1UF T 0 1UF 109 Tm 5 4 ces c23 T 100 MP3 C34 ro 100P 500V HST SP 3 5 ro i o2L33 3 1 03 1 04 2 4 1 06 6 5 4 15 54 1 05 7 7 0 lt 8 1 gt MEMORY cso Csi 52 5 5 css CS6 CS7 INT IRQ7 IRQ6 IRQS IROA IRO2 1 42 2 al 3 39 a 5 37 MS 1 35 B LW CS lt 7 gt 6 5 RESET 4 21 CLK 3 68M 20 D 7 0 vec R54 3K IRQ lt 5 gt U21 TMS9914AFN lt 7 0 gt DIOl DAV 297 DIO2 NRFD DIO3 NDAC DIO4 ATN DIOS REN DIO6 IFC DIO7 SRO EOI ACCGR RSO RS1 RS2 DBIN WE CE RESET ACCRQ INT TR CONT TE Do D1 D2 D3 D4 D5 D6 D7 ERRUPT L BOOT ROM ROM BANK O OR 1 ROM BANK 0 OR 1 REAL TIME CLOCK RAM RAM 18 0 18 1 CAL CONSTANTS BANK 0 FOR 128K PARTS BANK 1 FOR 128K PARTS DUART FOR EXTERNAL RS 232 PORTS DEBUG DUART UNUSED IEEE 488 INTERNAL 10MS TIMER UNUSED IEEE 488 INTERFACE EXTER
95. 19 C19 I ACDC IFBCK A19 C19 I ACDC c20 IFBCK A20 C20 I ACDC RCOMI A20 C20 RCOM2 A20 C20 2 EARTH 1 C21 RCOM2 RCOMI A21 C21 RCOM2 PMUX A21 C21 SMUX A21 C21 SMUX El6O 1 C22 SMUX PMUX A22 C22 SMUX SCOM A22 C22 SCOM A22 C22 SCOM ciod cix 1 OUTPUT BLOCK C23 560 A23 C23 SCOM mD A23 es C23 225 d p 1 C24 VMID A24 C24 SCOM A24 C24 VMID SCOM A24 C24 SCOM T 2007 T 200 1 SCHEMATIC C25 SCOM SCOM A25 C25 SCOM A25 C25 SCOM A25 C25 805 305 1 C26 A26 C26 A6 RET LO A26 C26 A6 RET LO OUT LO A26 C26 OUT LO HIGUARD TO GUARD 1 TOROIDS 27 OUT LO A27 OUT LO SNS LO 27 C27 6 SNS LO IN SNS LO A27 C27 IN SNS LO P201 1 7201 EE 28 SCOM A28 A28 C28 SCOM A28 4 OUT HI i MP c29 HIGUARD A29 29 29 HIGUARD A29 22 100MIL gt rs OUT HI c30 SLOT 0 C30 SLOT A30 c30 SLOT A30 ux gt 2 OSNS HI 2 C31 SLOT A31 C31 OT A31 C31 SLOT OUT HI A31 20MIL 1 3 MEE 2 OUT 220V OUT HI A37 OUT HI VDIV A327 32 VDIV IN SNS HI IN SNS K8 7 SNS HI 3 i Pe ee 1 8 125 26 127 20MIL 1 Lo E toate lt SNS HI gt IOP IOP 10 E us T T tooov T 1ooov T KEY 9202 2554 INSHIQUARD 5 1 lt 1 2 1 GUARD 6 E lt GUARD 1 OUT LO 7 1 3 OUT LO K 220V TO OUT L B 1 TOOMIL 1 4 1 x x7 OSNS LO 8 1 MES p
96. 1A6 lt 4C6 gt SHUNT SEL1 1A6 4C6 gt SHUNT SELO 1 6 lt 4C6 gt R176 LO CURR ENABLE 10 0K 15V 6 98K U29 lt gt Q41 Q42 MC34081 DN2535N3 R7 DN2535N3 LOCURR OUT ZA AAA lt gt 107 Ee HI CURR RTN vere aT A21 RCOM1 5V 016 1000P B MMBT3904 B R159 p 2 2 AQV225 6 98K 4 2 2 2 MP2 TEMP 1 2 I ACDC TEMP MON 2 22 22 ohe 15V 40 4 0 15 R143 1512 B U25 5 10 0K TEROR DG444 3 78 R37 R46 020 vE 2 61K 904 A20 3 R87 CR14 STBY 24 Sv Boake MMBD1503 IGND CAL OS o IGND IGND 2 11 15I2 E 330P 8 146 7 6 9 47 v R4 1 8K 110 Tii E 100 BOARD 57 R198 1B6 4C6 SHUNT SELO SHIELD 110 isv Eo ines acas SHUNT sELi1 7 16 MP7 R44 mE 15 EI SHUNT SEL2 7 E 511 i 10 lt SHUNT SEL3 8 7116 1512 v VIKING 4RO5T H 8 sv 15V 4D5 3B6 lt a 22 2 2A ENABLE 57LFC 1007 RCOM1 1 of 5 DIFFERENTIAL SHUNT AMPLIFIER Figure 6 5 A7 Current PCA cont 6 27 57LFC Service Manual GM 7 9A V AC 2 38A V DC 1A 1 19A V DC gt 1A w15 1 MONGO CED lt gt JUMPER MMBT3904 R55 4 02K CR4 MMBD1503 MP2 MJE15029 2 R72 ANA 99 100 MMBT3904
97. 1U 1 STURN L cios 1 4W 470 50V Res D8 12vGr 5 M 6TURN D 1 4W 1 GF1G TONES TP46 TP38 CR46 180M U20 L6 12 UNR 12VG 0 10 SOMIL ET t SOMIT a RT4 1015 AY 1A 12V 1 R69 cei 65 OUTGUARD SOMIL 22000 4 99K 0 1U QUT 10U MBRS140 0 1U SECONDARIES 25V GND TO220HS 25V TP29 TP34 180M 67 9 9 P1 0 1U GGND i 126 2 1343 2 2GCOM M2 3 __126 SOMIL 4 R87 c95 mam TO220HS CR63 C106 V 22000 0 1U 10U 0 1U KEY ggaca TP47 257 45885 7912 25v SEM 7 5GCOM 100MIL L10 13v 8 EN 582 100MIL SOMIL 7 oum 50MIL GND FROM POWER XFRMR CR50 GF1G Q GF1G 5VG UNR se TOOMIL CR22 inse22 6 TET 45VG UNR AE 5VG RT3 BI 582 GTURN CR27 1 5822 C47 CR49 C63 C 15000U MBRS140 0 1U GND TO220HS 100MIL 100MIL RT7 2 T 5COM 3ce VRE 100MIL 5235 VR9 SACL 8V 5235 100MIL TP40 180M 2 45UNR 2
98. 2 3 A5 Ohms PCA High Low Output 2 15 57LFC AN Service Manual BUFCOMPV ___ MN cow EXT kog CER NC COMP RES HI K12 HIGUARD 25 RCOM1 COMP_RES_LO K31 COMP_OUT_LO K21 Al apv003 eps Figure 2 4 A5 Ohms PCA High Low Sense Theory of Operation 2 A5 Ohms PCA Table 2 7 provides a functional description of the relay function for either the set or reset condition on the A5 Ohms PCA Table 2 8 provides information on the hardware control map for the relays and shows the relay setting for each state Table 2 9 shows the final relay states by instrument state Table 2 7 Functional Description of A5 Ohms PCA Relays Functional Description Reset Connect OHMS OUT LO to SGND Set Disconnect OHMS OUT LO from SGND Reset Connect 1 9 O Z1 resistance to OHMS OUT HI and OHMS SNS HI Set Disconnect 1 9 Q Z1 resistance from Reset Connect 1 9 Q Z1 resistance to OHMS OUT LO and OHMS SNS LO Set Disconnect 1 9 O Z1 resistance from LO Reset Connect 1 Z1 resistance to OHMS OUT HI and OHMS SNS HI Set Disconnect 1 Q Z1 resistance from Reset Connect 1 Z1 resistance to OHMS OUT LO and OHMS SNS LO Set Disconnect 1 Z1 resistance from LO Reset Connect 19 Q through 190 HI sense bus to OHMS 5 5 Set Disconnect 19 Q through 190 HI sense bus from OHMS SNS Reset Connect
99. 3 5B5 OTD VCCINT 1 0142 1 038 1 0141 1 039 VCCINT 1 040 1 0139 1 041 1 0138 GNDINT 1 0137 165 1 0136 1 044 GNDINT 1 045 1 0134 1 046 1 0133 B VCCINT 1 0132 COUT 15 ADDR 2 17048 70132 1 049 VCCINT 1 050 1 0129 1 051 1 0128 GNDINT 1 0127 1C8 2 SCALER OUT 11 0 1 053 1 0126 os 1 054 GNDINT 8B7 1 055 MSELO SYNC IN 1 056 MSEL1 1cs IG lt 7 0 gt VCCINT VCCINT 553 CBI 8D7 8B3 NCONFIG TMS CONFIG NCONFIG 807 8B7 6D8 DB7 DB0 TRST 8A7 807 TN STATUS B damsnoroZzoduansuoZooodansZorozH HZzsnZroooooozooooondZduiddddda PRI CH lt 15 0 gt 108 0000008000000050000090 80004848929009000900800000008920000009 c7 CVM SS SM S S S S N lt i ia SEC lt 15 0 gt HHHHHHHH HHHHHHHPHHHHHHH HHHPRARRBOHHPHHHHHHH HHHHHHHPHHHHHHHH I LITT I LLLI o ee o o e wipe ooo IG lt 7 0 gt 1 P 1 1 oojo lt e n o olo e 1C5 8B2 6D8 5D3
100. 33 UCNS800L UCNS800L 74HCUO4 U33 6 016 UCNS800L UCNS800L 74HCU04 U33 UCNS800L 02 UCNS800L Ui UCNS800L RLY STROBE 7 0 4 033 42 4 1734 9 10 11 12 U9 UCNS800L UNUSED 74HCUO4 74HCU04 U34 U34 4 9 q 8 3 q 74HCU04 74HCU04 034 034 d d 9 10 11 12 011 15 UCNS800L 7 lt 7 0 5RLH 9 10 11 12 U10 UCN5800L 12 74HCU04 U34 2 10 11 12 SET RST Us 16 15 Ds2E1 UCNS5800L D gt RR6 7 0 9 3 10 6 LE 5 12 713 UCN5800L 5 1 gt 10 9 10 11 12 8 UCN5800L 4A6 PULL DOWN CLR DRVR RLY RST 2 57LFC 1005 5 of 5 6 16 Figure 6 3 A5 Ohms PCA cont 6 Schematic Diagrams 57LFC 7606 von 1512 212 0214 au O goo 80 0 CR11 S
101. 35 400 ANN arraso 32400 gt 10 10 10 236520 SP 400 H S20 22 324600 10 5 NO VR37 45 MMSZ5263BT1 CR23 56V 324600 BAV99 8600 8400 PMOS 5 021 HVREG POS SP 600 i teu 555 324600 MMSZ5240BT1 10V 5 MMSZ5240BT1 VR56 1N6456A M 12 n 2 4 400V a N 5 R76 R78 R8 R84 SP 300 P108 56K 56K 56K 56K 2 R242 R252 R253 i C2 360UNR SP 600 249K 249K 249K 15V r gt ON OFF iov R243 5 200 ANA 4 7K 021 MC34081r MMSZ5240BTL 5 9 VRS7 1 5SMC47A 5 180UNR SP 300 MMSZ5240BT1 BAV99 CR22 CR37 C42 100P 15V BZG03 150V 5 024 MC34081 7 c7 180UNR SP 300 MMSZ5240BT1 4 U9 LM393DT 58 1 55 47 47V 5 ISZ5240BT1 5 10V 200K 10 0K R248 R254 R255 15V 249K 249K 249K R219 R223 R225 WA se VA era 56K 56K 56K VR59 1N6456A 400V Q41 5 VN0550 00 82 600 CR39 BAV99 MMSZ5263BT1 VR35 iov MMSZ5240BT1 2N6517 MMSZ5240BT1 10V 5 MMSZ5240BT1 5 SP 400 MP14 MP11 10
102. 4411A instrument The Booton is used below 30 kHz and the Agilent is used above 30 kHz A set of test limits is provided in Table 3 11 FLUKE 57LFC Booton 1130A mewo Resistor Divider with Optional PrE Switch Box 2 Hi Input 2M 20K Resistor Coax Cables Divider Agilent 4411A 00000000 g Input apv013f eps Figure 3 10 Harmonic Test Setup 3 19 57LFC AN Service Manual 3 20 Table 3 11 Harmonic Test Values for AC Volts _ Amplitude Frequency Load Reading Distortion mes mee mes exe 0 mes mes 0 mes wes 0 mes we mes wee _____ mos ewe ww mws mes we _ mes wes _____ mes 9 m we 6 m ee 6 m fon m fon heo m wes wee m eee 0 2 mes 0 2 wes om m 1 ms wee 0 mo eee 0 mo mes 0 ms wes 0 mo es pw 2 e w jw 2 mes ws jw Dua me wa 2 foes wn ww m wes Harmonic AC Current Test The harmonic ac current test ve
103. 50V COG 0805 867663 ERE ra CAPACITOR SMR CAP CER 0 1UF 10 50V X7R 1206 605292 EN CAPACITOR 100 20 25 6032 927814 CAPACITOR CERAMIC 0 1UF 10 25V X7R 0805 TAPE 942529 DIODE SI PN BAV99 70V 215MA 6NS DUAL SERIES SOT 23 TAPE 742320 DIODE SI PN S1G 400V 1A 1 8US DO 214AC TAPE 107573 5 41 57LFC AN Service Manual Table 5 7 A8 High Voltage PCA cont Part Description Number Qty DIODE SI PN GF1M 1000V 1A SMB TAPE 2060197 CURRENT REGULATOR DIODE CCLM1000 1 1MA 20 1 7 2043974 100V SOD80 TAPE DIODE MURS120 SMR DIODE SI ULTRAFAST 200V 1A SMB 944264 DIODE SI PN BAV199 70V 215MA 3US DUAL SERIES SOT 23 TAPE 605805 CR35 DIODE MBRS140 SMR DIODE SI SCHOTTKY 40V 1A DO 214AB 605821 2 CR48 CR42 CURRENT REGULATOR DIODE CCLM2000 2MA 16 2 3 2119594 1 SOD80 TAPE 2 2 FUSESX amp SMMO 2A2SOVSLOWRADAL 8X8 5MM 0 2A 250V SLOW RADIAL 851949 ES 1 K2 RELAY ARMATURE 2 FORM C 5VDC LATCH 603001 K4 CHOKESTURN S E E AE 6TURN 320911 EE INDUCTOR 1 5UH 596 128MHZ SHLD 413856 MP4 PCB HIGH VOLTAGE 02020200000 HIGH VOLTAGE 2048854 2 HEATSINK ASSEMBLY 2070059 MP5 MP3 HEATSINK ASSEMBLY 2070067 MP4 HEATSINK ASSEMBLY ASSEMBLY 2070032 a 5 42 List of Replaceable Parts 5 Parts Lists Table 5 7 A8 High Voltage PCA cont Ref Part Des Description Number Qty MP6 HEATSINK ASSEMBLY 2117189
104. 51 1 8 ED ro 22 1 PE 65728T 805 136 106 FIG A i6 8A7 FIG B 15V gt 203 1024 2241 1U 9 MDG444 964 064 TIG B c139 74 14 7AACT14 10 11 13 12 1i R201 gx i OOD s v 330P 22 1 TIG 5 zx R117 15V 499 15V 13 024 MDG444 CLR DRVR cas zoe WD RESET INJ eas CLR DRVR e 224 FAULT CLR 4 15V U16 74 00 IG FAULT OUT 016 4 74ACOO 4 064 IRFR120 064 74 00 74 14 222609 74ACT14 12 Q7 5V FAULT MMBT3904 105 ni cioe cio7 0 10 190 100 10 C79 O91 L____FAULT 0 XN 25v I 25 1 257 1 0 10 0 10 016 064 RLY TU cac RST A23 1 7 8 2 8 7 6 5 4 4 3 2 Figure 6 4 A6 Digital Synthesis cont Schematic Diagrams 5 4 V 1
105. 57LFC 57 Fc system INPUT SENSE 2WRE 4 WIRED 00000000 apv010f eps Figure 3 7 8508A Connections to the 57LFC for AC Current Measurement 57LFC AN Service Manual Table 3 8 AC Current Limits moe m m mes are ome mes __ are ome zeoas m sues m eos sermones ues ames os aroe es __ averse nes ames nes arrera m ao m e Dess aoe ames zroas aes zemess nones aos mos aoe m serena mes m senes mos e mes resemes aoo arses mes aos zozemes arrora 2 fe __ aem fa
106. 5MA 225MW SOT 23 TAPE 837187 iad VR16 VR6 VR9 ZENER UNCOMP MMBZ5235B 6 8V 5 20MA 225MW SOT 23 TAPE 837195 VR7 8 ZENER UNCOMP MMBZ5251B 22V 5 5 6MA 225MW SOT 23 TAPE 831230 VR10 ZENER UNCOMP SMBJ12A 12V 5 1MA 600W TRANSIENT 2002382 2 VR13 SUPRESSOR SMB TAPE VR11 12 ZENER UNCOMP 1 5SMC47A 47V 5 1MA 4W TRANSIENT 2086534 2 SUPRESSOR SMC TAPE VR14 15 ZENER UNCOMP 1 5SMC20A 20V 5 1MA 1 5KW TRANSIENT 2102456 2 SUPRESSOR SMC TAPE VR17 ZENER UNCOMP 1SMA24CA 24V 5 1MA 1W TRANSIENT 1572981 SUPRESSOR SMA TAPE List of Replaceable Parts 5 Parts Lists H1 16 RIVETS FOR DIN CAUTION SUBJECT TO DAMAGE BY STATIC ELECTRI
107. 5v R55 VDAC OUT SERY 203 IN ERROR INTEGRATOR ay LIN POLARITY INVERTER VOLTAGE ERROR OUT 1 U26 MDG444 13 Z MULT V lt 2 0 gt SNS LO DB101S VR3 950 11 11 LM393DT 5c7 R78 LIN 205K R59 205K C50 0 01U FAULT 7A7 050 500 2 SENSE COMMON MODE REDUCTION LM393DT 227 5520A 4RO9T H R77 55 555 i8 P106 FAULT DETECTOR 2 VMID A23 VMID 5000 28 50 505 15V 4 096 ADG411 DC COUPLE 1 css 2 3 RET LO NET PHYSICAL TYPE 200MIL A26 KV ENABLE 16 1 E 1 25 RET LO 15 14 2 2U PE LV ENABLE 9 10 nA LOCAL AC FB 8 TP12 v3 3 v S1 COMMON GRE BAS70 04 15V 5 044 1 LT1360 2 R101 TNA 4 BAT54S 57LFC 1 006 R80 R160 9 27 IoP 20K 1K EL 5 5 2 00K 3 of 8 AC DC AVERAGING CONVERTER 555 PRI XING STROBE S1 COMMON SES m DET T 9 15U RIPPLE FILTER 15V 2 6 20 Figure 6 4 A6 Digital Synthesis PCA cont Schematic Diagrams 1 I_PHASE IFBCK V
108. 6 AG DCOM AT CT DCOM IG DATAO AT IG IG DATAO AT C7 IG IG DATAO AT IG ADDRO AB CB IG ADDRi IG DATA2 AB IG DATA3 IG DATA2 AB CB IG DATA3 IG 2 AB IG ADDR2 AS IG ADDR3 IG DATA4 IG DATAS IG DATAZ IG DATAS IG DATA4 AS 9 200 A10 C10 DCOM IG DATA6 __ 10 IG DATA IG 6 __ 10 DATA IG DATA6 __ 10 IG CSO AIT DCOM 11 DCOM AIT DCOM 11 Q9 11 14 16 DCOM A12 C12 DCOM IG ADDRO __ 12 IG ADDRI IG ADDRO A12 C12 ADDRI IG ADDRO A12 R3 4 10 37 39 IG RD A13 C13 IG WR IG ADDR2 Ai3 IG ADDR2 A13 C13 ADDR3 IG ADDR2 Ai3 EE DCOM 214 Cia DCOM DCOM 214 DCOM 214 Cia DCOM 214 50MIL RLY RST A15 C15 FAULT A15 C15 IG CS0 A15 C15 IG A15 20MIL CLR DRVR A16 16 A16 C16 IG IG CS2 A16 C16 IG DCOM A17 C17 DCOM 217 C17 IG CS4 A17 C17 IG CS5 IG A17 57 Als C18 DCOM 18 C18 IG css Als C18 IG CS7 IG Als 5 A19 C19 5V DCOM A19 DCOM A19 C19 DCOM A19 DCOM A20 C20 DCOM IG RD A20 IG RD A20 C20 IG WR IG RDF A20 DCOM A21 C21 DCOM SPARE4 A21 SPARE4 A21 C21 SPAREO SPARE A21 5RLA A22 C22 DCOM A22 DCOM A22 C22 DCOM A22 DCOM DCOM A23 C23 DCOM RLY RST A23 FAULT RLY RST A23 C23 FAULT RLY RST A23 FAULT A24 C24 CLR DRVR A24 IG INT CLR DRVR A24 C24 IG INT CLR DRVR A24 IG INT A25 C25 DCOM A25 A25 C25 DCOM A25 DCOM A26 2 5V A26 C26 DCOM 57 26 A277 C27 A27 C27 5 A2
109. 7 A28 c28 DCOM A28 C28 DCOM A28 A29 29 DCOM A29 C29 DCOM A29 A30 5RLH A30 C30 5RLH A30 C31 DCOM 231 DCOM OGUA2 A3 C32 OGUA2 A32 C32 OGUA2 A32 5 ISHLD J108 J107 J106 J105 Al Al OGUA1 OGUAL Al OGUAL 360UNR AZ C2 360UNR MMONGO 22 C2 MMONGO 15V 2 C2 15 5 2 C2 15V 180UNR A3 C3 180UNR A3 SCOM A3 SCOM 45V 45V MMCOM A4 15V A4 15V 215 A4 15V SCOM C5 SCOM A5 C5 SHORT AS C5 OTD C5 45V MMONGO MMONGO A6 C6 SRC A6 C7 180UNR 7 C7 IREF AT C7 SCOM AT SCOM CB 360UNR 151 CB 151 8 CB 5 AB CB 45V cs ICOM A9 Co ICOM AS co SCOM A9 co SCOM cio 151 15 A10 A10 C10 45V cii ISHLD ISHLD All cii SCOM 11 5 C12 SCOM SCOM A12 C12 SCOM A12 C12 3 A12 C12 3 C13 15V 15 A13 C13 15V SCOM Al3 C13 SCOM A13 C13 SCOM e SCOM SCOM TC LO Cia MEAS Ald C15 15V 15V A15 C15 15V TC COMP A15 C15 TC ISO SRC 15 C15 C123 130 NOT INSTALLED C16 SCOM SCOM 16 C16 SCOM TC ISO MEAS A16 C16 TC SRC Aie C16 C17 V3 3 17 17 3 SCOM 17 CLT SCOM A17 C17 SCOM P201 IS A 3 PIN HEADER FOR PINS 1 TO 3 AND C18 SCOM SCOM Als C18 SCOM I PHASE A18 Ai8 C18 A 5 PIN HEADER FOR PINS 5 TO 9 I PHASE A19 19 IFBCK A
110. 7282 TL062 SMR IC OP AMP DUAL JFET LOW POWER SOIC 806794 List of Replaceable Parts 5 Parts Lists Table 5 5 A6 Digital Synthesis PCA cont Number Qty BIPOLAR LM393 SMR IC COMPARATOR DUAL LOW PWRSOIC LM393 SMR IC COMPARATOR DUAL LOW PWR SOIC 837211 021 044 AD823 SMR IC OP AMP DUAL RAIL RAIL 16 MHZ SO8 642709 59 ICANALOG SWITCH ADG431 5 44V 24 OHMS SPST NO SO16 TAPE ANALOG SWITCH ADG431 5 44V 24 OHMS SPST NO SO16 TAPE 689844 X 030 034 EDS SMR RELAY SOLID STATE 1FORM A 80VDC 120MA 687217 U38 U31 U37 IC OP AMP LT1630 2 7V TO 15V 525UV OFFSET 15MHZ R R S 2075118 2 S DUAL SO8 TAPE U33 U48 IC OP AMP LTC1150 16V 10UV OFFSET 2 5MHZ ZERO 2051666 4 052 53 DRIFT CHOPPER DIP8 TUBE BIPOLAR OP284 SMR IC OPAMP DUAL PRECN RAIL RAIL 1 0 508 642691 ISOLATOR OPTO SMR ISOLATOR OPTO LED TO TRANSISTOR SOIC 929281 BIFET LF356N IC OP AMP JFET INPUT 8 PIN DIP 472779 IC VOLTAGE REGULATOR LINEAR LM2990 15V 1A LDO TO 220 TUBE 2111724 BIPOLAR 2940 IC VOLT REG LDO 15 V 1 0 A TO 220 602748 VR1 VR5 ZENER UNCOMP MMBZ5237B 8 2V 5 20MA 225MW SOT 23 TAPE 837146 ZENER UNCOMP MMBZ5231B 5 1V 5 20MA 225MW SOT 23 TAPE 837179 VR2 VR3 4 ZENER 1N5908 ZENER TRANS SUPPRESSOR 6V 508655 W1W5 7 CONNECTOR JUMPER COPPER TIN 1206 SURFACE MOUNT T R 2061468 SUBSTRATE ASSY 5500 4 02 945316 24 THIN FILM HERM RESISTANCE REF 2094985 5 29 57LFC A
111. 769869 3 R47 RESISTOR SMR RES CERM 110 1 125W 100PPM 1206 644473 5 R49 RESISTOR WIREWOUND 1 0 0 5 1W 50PPM 2515 TAPE 1544336 2 R50 RESISTOR SMR RES CERM 10 1 125W 100PPM 1206 867676 2 5 35 57LFC AN Service Manual 5 36 Table 5 6 A7 Current PCA cont aces i RESISTOR SMR RES CERM 4 02K 1 125W 100PPM 1206 783266 T R67 68 RESISTOR SMR RES CERM 1M 1 125W 100PPM 1206 836387 R78 79 RESISTOR CERMET 47 5 1 0 1W 100PPM 0805 TAPE R81 82 RESISTOR SMR RES CERM 4 99K 1 125W 100PPM 1206 RESISTOR SMR RES CERM 4 32K 1 063W 100PPM 0603 R100 RESISTOR SMR RES CERM 4 99K 1 0 1W 100PPM 0805 928767 R103 R104 RESISTOR SMR RES CERM 49 9 1 0 1W 100PPM 0805 604923 R107 RESISTOR SMR RES CERM 1M 5 063W 200PPM 0603 604998 RESISTOR SMR RES CERM 10K 1 0 1W 100PPM 0805 928791 R146 RESISTOR SMR RES CERM 1 8K 5 125W 200PPM 1206 746453 R159 RESISTOR SMR RES CERM 6 98K 1 125W 100PPM 1206 929919 R173 R186 RESISTOR SMR RES CERM 301 1 125W 100PPM 1206 644598 R207 RESISTOR SMR RES CERM 49 9 1 0 25W 100PPM 1210 929674 208 POWER TRANSFORMER 16 5V 43 6VCT 627031 CONNECTOR TERMINAL TEST POINT 1510 TAPE 602125 IC BIMOS 4 CHNL DRVR W LTCH SOIC 929781 List of Replaceable Parts 5 Parts Lists Table 5 6 A7 Current PCA cont Part Description Number Qty 929992 5 875232 021 044
112. 8 V 188 V 110 V to 220 V dc 375 V 188 V 110 V to 220 V dc 188 V 375 22V to 101 V ac 188 188 101 V to 220 V ac 375 V 375 The amplifier input stages are operated from 15 V rails Regulator circuits for the high voltage rails are located on the A8 High Voltage PCA while the 15 V rails are derived externally In the 220 V range relays and route the input signal V3 3 and it s associated ground from connector P108 to the inverting and non inverting inputs respectively of an operational amplifier input stage comprising U3 and U4 The combination of wide bandwidth amplifier U3 and chopper stabilized amplifier U4 allows wide bandwidth and good DC performance to be achieved simultaneously Transistors 031 and Q32 diodesVR22 and VR42 and resistors R129 and R130 form a feedback voltage clamp around the op amp to ensure the output and inverting input always remain within their linear operating range This is necessary to prevent conditional large signal instability of the 220 V amplifier resulting from the finite overload recovery time of the op amp Dual diode CR30 clamps the op amp inverting input at approximately 0 7 V under overload conditions The output of U3 is fed via R131 to voltage to current converter stage Q53 The transconductance of this stage is set by R199 and emitter bias current is provided by current source Q54 Diode CR29 is included to prevent reverse base emitter breakdown o
113. 9 BAV99 1 00K MMBT3 o ho iov 9 VR20 8252408 55 2 R124 SGND MP13 MTP2P50E MMSZ5245HT1 IRF820 TO220HS Q1 MP2 IRF820 TO220HS MURS12 MMSZ5245BT 15V 5 PN3640 R107 1 N R109 9 ISZ5240BT1 Q50 2N3904 82 400 sp 400 MMBT3906 MMSZ5240BT1 10V 5 MMSZ5240BT1 R111 10V 5 MMSZ5226 5 3 3V MMSZ5245BT1 5 15V 470 MURS120 1021 2 50 TO220HS TO220HS R236 24 3K 24400 915 4 70P196GS 061 MJD350 l Q13 MJD350 MMSZ5240B 5 10V MJD350 014 8 200 4 377400 8 300 2 MJD350 3 400 C7 3 3U 450V 32 200 9 m 916 OP196GS 15V SGND VA I NEG 063 D340 62 MJD340 32 400 95 400 C70 0 1U 016 MJD340 n MMSZ5240B 5 107 57 100 8 OUT 220V A32 9 4 5 400 A 6 11 5 400 R127 ANN 09200 100K 2 57LFC 1008 2 of 4 ca2 6 34 Figure 6 6 A8 High Voltage PCA cont Schematic Diagrams 7 5 j 4 3 2 1 MP9 POS R72 R70 R71 SP 600 5600
114. B5 DB4 DB3 DB2 SCALER DAC 11 0 WR cs SEC CHANNEL SCALE DAC REFERENCE DESIGNATON NOT USED C148 149 CR12 5 P2 105 107 205 R134 135 144 151 R155 158 171 195 U49 63 68 70 72 81 U85 86 88 89 91 94 DDS2 OUT NOTES UNLESS OTHERWISE SPECIFIED 1 2 RESISTORS ARE IN OHMS 1 TOLERANCE CERM OR MF SURFACE MOUNT NON POLARIZED CAPACITORS ARE CERAMIC 25V 50V OR 100V SURFACE MOUNT POLARIZED CAPACITORS ARE TANTALUM 57LFC 1006 1 of 8 6 18 Figure 6 4 A6 Digital Synthesis PCA cont 5 Schematic Diagrams 4 210 11 34 8K L12 220 OHM 15V 8 L 6 7 p U58 4 LTC1151C 15V 2B6 2C3 505 VDAC X2 210 34 8K C88 7VREF 2 5 2B3 286 2D3 505 IDAC X2 104 5C7 058 220 OHM 4 LTC1151C ai c71 12 15520 4 10 pba 211 34 8K 2 IDAC OUT
115. CA 6 5 57LFC Service Manual 8 7 6 5 4 3 NOTES UNLESS OTHERWISE SPECIFIED REFERENCE DESIGNATON 1 ALL RESISTORS ARE IN OHMS ALL CAPACITORS ARE IN FARADS NOT USED C7 9 13 16 A8 VOLTAGE A7 CURRENT A6 DDS A5 OHMS CR30 32 9 E9 J208 NC J207 J206 J205 OGUA3 Al OGUA3 Al OGUA3 CLIN A Al SER A 1 DCOM A2 C2 DCOM A2 2 CLIN B A2 C2 SER B 5 A2 92 5 7 104 109 202 IG DATAO A3 C3 IG DATAi A3 CLOUT A3 TIG A3 J204 IG DATA2 IG DATA3 B TIG B IG DATAZ AS C5 IG DATAS AS SPARE2 FIG AS C5 FIG B SPARE1 AS IG DATAG A6 IG DCOM AG DCOM A
116. CITY e g E gen o 5 52810 E 4 gt 1 2 sIf 3 5 Ig 2 g 2 o iB EN B ETT i E s EM E pa iip 5 o Er TOP VIEW CKT 6 57LFC 4003 apv053f eps Figure 5 3 A3 Motherboard PCA 5 17 57LFC AN Service Manual Table 5 4 A5 Ohms PCA Ref Part Des Description Number Qty C1 C18 CAPACITOR SMR CAP TA 10UF 20 25V 6032 927814 12 C39 C42 C47 48 C82 83 C85 C88 C96 97 C2 17 CAPACITOR SMR CAP CER 0 1UF 10 50V X7R 1206 605292 C19 21 C23 36 C38 C40 CAPACITOR SMR CAP CER 0 047UF CAPACITOR SMR CAP CER 0 047UF 20 50V X7R 1206 50V X7R 1206 782615 m C37 C74 CAPACITOR CERAMIC 100PF 5 100V COG 0805 TAPE 601028 B C76 C93 C41 C46 CAPACITOR CAP AL 1000UF 20 16V SOLV PROOF 837468 C79 80 CAPACITOR SMR CAP CER 0 1UF 10 100V X7R 1206 804325 Eus 95 00 CAPACITOR SMR CAP CER 68PF CAPACITOR SMR CAP CER 68PF 2 50V C0G 0805 50V C0G 0805 802090 EM CR1 3 SMR DIODE SI DUAL 50V 250MA SOT 23 851659 CR7 8 DIODE SI PN DF01S 100V 1A BRIDGE 4 PIN SURFACE 912456 NEN 3530 TAPE CR5 6 6 DIODE MBRS140 SMR DIODE SI SCHOTTKY 40V 1A DO 214AB MBRS140 SMR DIODE SI SCHOTTKY 40V 1A DO 214AB 605821 2 DIODE SI PN BAV199 70V 215MA 3US DUAL SERIES S
117. ENABLE UL 698 REO LO_CURR_ENABLEDT iss pos SOFT START 7 698 4 04 MP3 TEMP MON MP2 TEMP MON CAL OS 74HC374 SET 16 DS4E 19 SHUNT SEL3 15 SHUNT 12 SELO 2 _____CoMEz UCNS800L COMP3 5 O lt 74HC374 UL 8 714 UCNS5800L 74 04 UCN5800L IG_DATA lt 7 0 gt SET 16 DS4E 911 UCNS5800L 92 74HC138 CR6 9 MMBD1503 10 IL 12 01 012 UCN5800L 74AC04 5RLH 57LFC 1007 4 of 5 IG CS3 DIGITAL CIRCULTRY A24 CLR DRVR A23 RLY RST 5 4 3 2 Figure 6 5 A7 Current PCA cont 6 30 Schematic Diagrams CR27 X wprsi40 129 0 0470 2 D MI 1 4 CR29 548 5
118. ERMET 68K 2 0 75W 200PPM 2010 TAPE 2062916 5 45 57LFC AN Service Manual Table 5 7 A8 High Voltage PCA cont Part Description Number Qty RESISTOR SMR RES CERM 10K 196 0 1W 100PPM 0805 928791 RESISTOR 110 5 0 75 200 2010 2060968 RESISTOR 150 5 0 25 200 1206 TAPE 2060922 5 46 List of Replaceable Parts 5 Parts Lists Table 5 7 A8 High Voltage PCA cont Part Description Number Qty RESISTOR CERMET 56K 5 0 75W 200PPM 2010 TAPE 2060910 RESISTOR SMR RES CERM 150 5 125W 200PPM 1206 746313 rtu RESISTOR CERMET 10K 596 0 25W 200PPM 1210 TAPE 1597827 RESISTOR 120 1 0 25 100 1206 2062893 RESISTOR CERMET 280K 596 0 25W 200PPM 1206 TAPE 2060979 RESISTOR 10 10 1 200 2512 2113674 RESISTOR CERMET 33 2K 1 0 1W 100PPM 0805 TAPE 943345 5 47 57LFC AN Service Manual 5 48 Table 5 7 A8 High Voltage PCA cont Part Description Number Qty E RESISTOR METAL FILM 48 7K 0 1 0 1W 25PPM 0805 TAPE 1544262 e R155 RESISTOR SMR RES CERM 100K 1 0 1W 100PPM 0805 928866 s RESISTOR CERMET 3 16K 1 0 1W 100PPM 0805 TAPE 943019 RESISTOR CERMET 330K 5 0 25W 200PPM 1206 TAPE 2060931 RESISTOR CERMET 9 1K 5 0 1W 200PPM 0805 TAPE 2060946 RESISTOR CERMET 8 2 1 0 25W 100PPM 1206 TAPE 2123526 RESISTOR CERMET 3 3 1
119. FLLIKE o LFC AN System Calibrator Service Manual March 2004 2004 Fluke Corporation All rights reserved product names are trademarks of their respective companies LIMITED WARRANTY AND LIMITATION OF LIABILITY Each Fluke product is warranted to be free from defects in material and workmanship under normal use and service The warranty period is one year and begins on the date of shipment Parts product repairs and services are warranted for 90 days This warranty extends only to the original buyer or end user customer of a Fluke authorized reseller and does not apply to fuses disposable batteries or to any product which in Fluke s opinion has been misused altered neglected contaminated or damaged by accident or abnormal conditions of operation or handling Fluke warrants that software will operate substantially in accordance with its functional specifications for 90 days and that it has been properly recorded on non defective media Fluke does not warrant that software will be error free or operate without interruption Fluke authorized resellers shall extend this warranty on new and unused products to end user customers only but have no authority to extend a greater or different warranty on behalf of Fluke Warranty support is available only if product is purchased through a Fluke authorized sales outlet or Buyer has paid the applicable international price Fluke reserves the right to invoice Buyer for importation costs
120. Frequency Accuracy Fluke 85084 or equivalent ACV Accuracy Fluke 8508A or equivalent DC Current Fluke 85084 or equivalent AC Current Fluke 8508A characterized by a Fluke 5720 or equivalent Resistance Fluke 8508A or equivalent Lo 0 00 0 0 Harmonic Test Levels for AC Volts Booton and Agilent Analyzer with resistor divider Harmonic Test Levels for AC Current Booton and Agilent Analyzer with resistor divider External Trigger No external trigger mechanism is available on NA the Calibrator Voltage Output Compliance Test Fluke 8508A or equivalent with 440 W 22 V or 11 kW load resistor 220 V Current Output Compliance Test Fluke 8508A or equivalent with 1 8 combined shunt resistance Chapter 4 Maintenance MTOM CU sio ttt en PO EROR 4 3 Replacing th Buses u na Cleaning the Filter a u sa aa n aa qana Replacing PCA Modules Cleaning the Exterior 57LFC AN Service Manual 4 2 Maintenance 4 Introduction Introduction This chapter explains how to perform the maintenance tasks required to keep your calibrator in optimal operating condition The tasks covered in this chapter include the following e Replacing the fuse e Cleaning the air filter and external surfaces e Replacing the PCA modules Replacing the Fuse A ACaution To prevent instrument damage verify that the correct fuse is installed for the line voltage setting The line power fuse is accessib
121. LT1781 DUAL RS 232 LINE DRIVER RECEIVER 2101104 20 15KV ESD SOICW16 TAPE SMR IC NMOS GPIB CONTROLLER PLCC 887190 SMR IC LSTTL OCTAL GPIB XCVR SOIC 831651 SMR IC LSTTL OCTAL GPIB XCVR SOIC 831669 IC MEMORY SRAM K6T1008 1MB 128KX8 5V 100NS SO32 TAPE 914101 4 35 Y1 CRYSTAL 12 288MHZ 50 100PPM 20PF PLASTIC 913942 ENCAPSULATED SMD TAPE Y2 CRYSTAL 3 6864MHZ 100 100PPM 20PF PLASTIC 929240 ENCAPSULATED SMD TAPE RESISTOR SMR RES CERM ARRAY 4 PIN 2 RES 1K 5 644861 2 5 58 List of Replaceable Parts 5 Parts Lists 20 0000000000000000 R 1 12 11 CKT 6 VIEW ION BY 57LFC 7609 STATIC ELE 1 of 1 058 Figure 5 8 9 Out Guard 5 59 Figure 6 1 ON ON O O O 2 3 4 5 6 B A LED PCA A3 Motherboard PCA A5 Ohms PCA A6 Digital Synthesis PCA A7 Current PCA A8 High Voltage PCA A9 Out Guard CPU PCA Chapter 6 Schematic Diagrams Title Page 57LFC AN Service Manual 6 2 Schematic Diagrams 6 CAUTION SUBJECT TO DAMAGE BY STATIC ELECTRICITY WHITE 57LFC 7601 1 of 1 Figure 6 1 A1 LED PCA 6 3 57LFC Service Manual WARNING OPERATE
122. N Service Manual CAUTION SUBJECT TO DAMAGE STATIC ELECTRICITY su se goo PT TENE E Wa 08 TE B mi 3 sag cen 08 ed 0 1138 lt 12 Cores 05 r us mm 5 Sel _ 5 O 57LFC 4006 055 Figure 5 5 A6 Digital Synthesis 5 30 Table 5 6 A7 Current PCA Ref Part Des Description Number Qty 101 ISOTHERMAL RET 690500 C1 C3 6 CAPACITOR SMR CAP CER 0 1UF 10 50V X7R
123. NAL DUART REAL TIME CLOCK DEVELOPMENT DUART WATCHDOG TIMER EVEL ASSIGNMENTS IEEE 488 CONNECTOR MPSWIREPOINTS TO GND FOR MOUNTING HOLES 25 SH 75ALS160N 2 BIOS 16 111 U24 3 8107 15 19 4 BIOG 14 11 5 5 22 s BIOS Li 7 BIOS Li B DIO2 2 L2 9 DIOI i 11 TE 70 OHM 1725 lt 8 ATN 11 12 EOI 7 5 14 SRO 5 SR io L2 REN 2 REN E 17 114 IFC 3 IFC 12 DAV 6 DAV 6 11 4 NDAC 8 L24 NRFD 5 NRFD 7 11 70 OHM 18 19 20 SN75ALS161DW 21 22 23 24 i2 425 sH MTG HOLES OF J4 ARE TIED TO CHASSIS GND 57LFC 1009 2 of 2 Figure 6 7 A9 Out Guard CPU PCA cont 6 39 57LFC Service Manual 6 40
124. OT 23 TAPE 605805 CR11 DIODE SI PN S1G 400V 1A 1 8US DO 214AC TAPE 107573 4 CR15 CR17 18 RIVET AL 089 DIA 344 L SEMI TUBULAR OVAL HEAD 838458 List of Replaceable Parts 5 Parts Lists Table 5 4 A5 Ohms PCA cont Part Description Number Qty RELAY ARMATURE 2 FORM C 5VDC LATCH K2 5 K8 RELAY ARMATURE 4 FORM C 5V LATCH 715078 14 K16 19 K27 35 K38 p K41 rm RELAY ARMATURE 2 FORM C 5 VDC LATCH 910773 ENI INDUCTOR BEAD 95 OHMS 100MHZ 1ADC 1MOHM 3612 TAPE 867734 2048822 MP4 5 5 EJECTOR EJECTOR PWB NYLON EJECTOR PWB NYLON 494724 P105 CONNECTOR DIN41612 TYPE C RT ANG 64 PIN 807800 PNP MPS6562 ROSA TRANSISTOR SI PNP 25V 1 5W T0 92 MPS6562 ROSA TRANSISTOR SI PNP 25V 1 5W T0 92 698290 mnm ROSR TRANSISTOR SI NPN 25V 1 5W SEL TO 92 685404 nm MOSFET P CHANNEL TRANSISTOR SI P MOS ENHANCEMENT TO 72 P CHANNEL TRANSISTOR SI P MOS ENHANCEMENT TO 72 741058 MOSFET SI N SD210 30V 50MA 45 OHMS 300MW DMOS LOW 394122 1 CAPACITANCE TO 72 BULK TRANSISTOR SI PNP 2N5401 160V 600MA 100MHZ 350MW AMMO 698274 s TO 92 TAPE NPNMPSA42 ROSA TRANSISTOR SI NPN 300V 1W TO 92 MPSA42 ROSA TRANSISTOR SI NPN 300V 1W TO 92 722934 R1 4 5 es SMR RES CERM 2 2M 596 125W 200PPM 1206 811778 R28 R2 R14 RESISTOR CERMET 100 1 0 125W 100PPM 1206 TAPE 867494 R17 R22 RESISTOR SMR RES CERM 1K 1 125W 100PPM 1206 783241 RESISTOR SMR RES CERM 10
125. R 0 0 05 MAX 0 063W 0603 TAPE 604394 R6 RESISTOR SMR RES CERM 51 1 196 125W 100PPM 1206 806422 2 R13 RESISTOR SMR RES CERM 499 1 125W 100PPM 1206 867833 R11 RESISTOR SMR RES CERM 3K 5 125W 200PPM 1206 746511 60 RESISTOR SMR RES CERM 27 596 125W 200PPM 1206 807735 15 RESISTOR SMR RES CERM 1K 596 125W 200PPM 1206 745992 RESISTOR SMR RES CERM 390 5 125W 200PPM 1206 740498 RESISTOR SMR RES CERM 3 6K 5 125W 200PPM 1206 746537 RESISTOR SMR RES CERM 10 7K 1 0 1W 100PPM 0805 930037 RESISTOR SMR RES CERM 1K 5 125W 200PPM 1206 745992 SWITCH SLIDE SPDT LOW PROFILE 911250 SMR IC CMOS MICROPROCESSOR SUPERVISOR SO8 929224 U3 U4 05 02 SMR IC TTL DUAL RS422 DRVR RCV W 3ST SOIC 913827 l O W CRYSTAL SO24 TAPE IC VOLTAGE REGULATOR LINEAR LP2980 5V 50MA LDO LO 944996 PWR W SHUT DOWN SOT 23 5 TAPE IC MEMORY FLASH 28F004 4MB 512KX8 5V 80NS BOTTOM 689232 BOOT PROGRAMMED U5 TSOP40 TRAY 5 57 57LFC AN Service Manual Table 5 8 A9 Out Guard PCA cont Ref Part Des Description Number Qty U6 IC MEMORY FLASH 28F004 4MB 512KX8 5V 80NS BOTTOM 689239 BOOT PROGRAMMED U6 TSOP40 TRAY U7 IC LOGIC 75704 1 8V 5 5V INVERTER SC70 5 TAPE 1541155 U8 CMOS 752125 SMR IC CMOS SINGLE BUFFER W 3 ST SOT 23 5 690765 ks CMOS 752126 SMR IC CMOS SINGLE BUFFER W 3 ST SOT 23 5 689304 U9 BIT 5V 16MHZ INTEGRATED PQFP132 TRAY U19 INTERFACE
126. R CAP CER 10PF CAPACITOR SMR CAP CER 10PF 5 50V C0G 0805 50V C0G 0805 494781 ES C28 C30 CAPACITOR SMR CAP CER 0 22UF 10 25V X7R 1206 106625 31 C36 37 CAPACITOR RO5A CAP AL 47UF 20 50V SOLV PROOF 822403 B C50 C108 C39 C43 CAPACITOR SMR CAP TA 10UF 2096 25V 6032 927814 44 C61 C76 C98 C40 C42 CAPACITOR RO5A CAP AL 100UF 20 16V SOLV PROOF 816850 EE C85 C70 CAPACITOR CAP AL 15000UF CAPACITOR CAP AL 15000UF 20 16V 25x30 16V 25X30 803764 EN C87 CAPACITOR CAP AL 47000UF 20 16V 601259 C54 071 C71 CAPACITOR CERAMIC 0 01UF 10 50V X7R 0805 TAPE 106146 C78 CAPACITOR CAP AL 2200UF 20 25V SOLV PROOF 782383 C72 C90 CAPACITOR ELECTROLYTIC ALUMINUM 3300UF 2065600 4 C93 94 2096 35V 22X25 BULK List of Replaceable Parts 5 Parts Lists Table 5 3 A3 Motherboard PCA cont Description Number Qty C73 74 CAPACITOR CAP AL 47UF 20 400V SOLV PROOF 782532 EE 92 C101 101 CAPACITOR CAP AL 330UF CAPACITOR CAP AL 330UF 20 100V SOLVPROOF 100V SOLV PROOF 816785 C84 C97 CAPACITOR SMR CAP CER 0 1UF 1096 100V X7R 1206 804325 EN cto CAPACITOR R05A CAP POLYES 1UF CAPACITOR R05A CAP POLYES 1UF 10 50V 50V 733089 1 CR1 2 DIODE SI 125V 200MA DO 35 802550 EH DIODE SI PN S1G 400V 1A 1 8US DO 214AC TAPE 107573 36 CR12 CR14 CR16 17 CR20 2
127. RESET 18 R5 28 16 2 3 T DS 1 0 0 A15 DRAMA14 F DS A14 DRAMA13 010 014 IS DRAMA REF DES PARTNAME GGND V lt 12 0 11 68C681CJ JTAG POR A11 DRAMA10 7 aa TXDA U2 DS8923A 3 ARRAS 23 100PF RTC64613 1 12 21 24 Ag DRAMA7 D10 RXDB Us E28F004BL 23 39 30 31 21 DRAMAG pn e 06 E28F004BL 23 39 30 31 R8 55 OP6 010 MC68306 1 13 22 7 28 40 nia 3K Ds 085 34 46 55 61 73 94 4 4 BERR D3 67 79 88 106 127 DTACK D2 OP2 100 112 Di opi 14 02 121 iL 014 68C681CJ 22 44 R W Ips 42 021 TMS9914AFN 22 44 Drack C3 U24 SN75ALS160DW 10 20 B sug gpa U25 SN7SALS161DW 10 20 24154 rack Ipo 8 5 38 RESET Q TO INGUARD CPU 2 X1 CL T 12 37 36 DS8923A 16 1 15 C71 NOTES R6 12MHZ T LL PART NOT INSTALLED 22PF 2 22 V V DTACK lt 15 0 gt EDS gt RI 3A82 4 CLK 3 68M gt 2 8 3 8 OE V BAK vec A RST J 155 8 lt 2 gt 2 4 CS us PULLED UP TO V BAK AT THE RTC CHIP 8 782126 782125 57LFC 1 009 EE i 2 8 7 6 5 4 3 2 Figure 6 7 A9 Out Guard CPU PCA cont 6 38 Schematic Diagrams 1
128. RRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE FLUKE SHALL NOT BE LIABLE FOR ANY SPECIAL INDIRECT INCIDENTAL OR CONSEQUENTIAL DAMAGES OR LOSSES INCLUDING LOSS OF DATA ARISING FROM ANY CAUSE OR THEORY Since some countries or states do not allow limitation of the term of an implied warranty or exclusion or limitation of incidental or consequential damages the limitations and exclusions of this warranty may not apply to every buyer If any provision of this Warranty is held invalid or unenforceable by a court or other decision maker of competent jurisdiction such holding will not affect the validity or enforceability of any other provision Fluke Corporation Fluke Europe B V P O Box 9090 P O Box 1186 Everett WA 98206 9090 5602 BD Eindhoven U S A The Netherlands 11 99 To register your product online visit register fluke com Claims Immediately upon arrival purchaser shall check the packing container against the enclosed packing list and shall within thirty 30 days of arrival give Fluke notice of shortages or any nonconformity with the terms of the order If purchaser fails to five notice the delivery shall be deemed to conform with the terms of the order The purchaser assumes all risk of loss or damage to instruments upon delivery by Fluke to the carrier If an instrument is damaged in transit PURCHASER MUST FILE ALL CLAIMS FOR DAMAGE WITH THE CARRIER to obtain compensation Upon request by purchaser Fluke
129. The differential drive for the output transistors 15 obtained from U7 058 Q5 Q3 and associated components The positive output transistor drive voltage across R23 is obtained from current supplied by Q5 Q5 is configured as a common base amplifier Current from R25 in the emitter of Q5 is passed out of the collector and into R23 Q5 is biased by of amplifier U58 R6 and R12 form a divider across the 151 supply to 2 41 57LFC AN Service Manual provide 2 V at the positive input of 058 The negative input of U58 is connected to the emitter of Q5 U58 will therefore drive the base of Q5 to keep the emitter of Q5 at 2 V The input to the mid current output amplifier is amplified by U7 The output of U7 is connected to R25 R28 and R27 R84 With zero input voltage the output of U7 will be zero The current through R25 R28 will be 2 mA 2 V 1 K The 2 mA through R25 R28 will be passed through Q5 to R23 to provide a voltage of 242 mV 2 mAx121 Q The voltage at emitter of MP13 tracks the voltage on R23 as explained above With the 1 Q resistor R53 switched in the bias current will be 242 mA 242 mV 1 With the 10 resistor R50 switched in the bias current will be 27 mA 24 2 mV 9 1 2 10 O in parallel with 100 2 9 1 2 The negative output transistor drive operates in a similar manner Drive voltage across R32 is obtained from the collector of Q3 Q3 is a common base stage biased to 2 volts by the other of 058 an
130. UX line Next set the OCHK register to the DIAG state for measuring LO and measure the SMUX line This reading should be less than the limit given in the Table 2 14 If not there is likely a relay or resistor problem Save this reading for subtracting from the following HI measurement Next set the OCHK register to the DIAG state for measuring and measure the SMUX line Subtract the LO reading divide by the Ichk current and compare the resistance with the calibration value The difference should a couple percent If the difference is too large there s likely a relay resistance or diagnostic circuit problem 2 29 57LFC AN Service Manual Table 2 12 OTEST Register States by Instrument State Control Register OTEST Signal ISEL ISEL ISEL ISEL ISEL ZIVR IN IN MA HUA TUA UA HNA EF IVREF RCO M Instrument State Bit 4 2 1 4 2 1 Weight MN EUNTEM i D n Any Q 2 4 Oper or STBY or Measure Vcompl DIAG 1 5 to 3 3 mA Ichk DIAG 150 to 330 uA h L h h h h L L bc Ichk DIAG 15 to 33 h h L h h h L L dc Ichk DIAG 1 5 to 3 3 uA h h h L h h L L ec Ichk DIAG 150 to 330 nA f4 Ichk Key x don t care h high off de asserted L low on asserted Table 2 13 OCHK Register States by Instrument State Control Control Register OCHK CK CKHI CKLO CK IVREF EXTRA COMP FAULT Instrument State 1 Bit Weight
131. V 7343 CAPACITOR SMR CAP CER 1000PF 10 50V X7R 0805 C24 CAPACITOR SMR CAP CER 0 01UF 10 50V X7R 0603 C28 29 5 55 57LFC AN Service Manual 5 56 Table 5 8 A9 Out Guard PCA cont Part Description Number Qty CAPACITOR SMR CAP TA 10UF 20 25V 6032 927814 CAPACITOR SMR CAP CER 100PF 1096 500V CO0G 1206 691508 CAPACITOR SMR CAP CER 0 1UF 10 25V X7R 1206 747287 CAPACITOR SMR CAP CER 100PF 1096 500V CO0G 1206 691508 B CAPACITOR 100 2090 25 6032 927814 For ememmsmcecmew mewcmws 1 sonews92 250PANPRLUPS STEEL2ne cLEARLOGK 2 Fi e ar Pa CONNECTOR CONN MICRO RIBBON REC PWB 24 POS INDUCTOR BEAD 70 944558 OHMS 100MHZ 200MADC 500MOHM 1206 TAPE L9 24 INDUCTOR BEAD 70 944558 16 OHMS 100MHZ 200MADC 500MOHM 1206 TAPE MP 1 2 STANDOFF ROUND 6 32 220 HEIGHT 250 OD BRASS SWAGE 062 261727 2 Cee 34 THK MP3 5 SPACER SWAGE 250 RND BR 6 32 250 SWAGE 250 RND BR 6 32 250 446351 RUBBER PAD PORON 75 75 125 SSA 690495 CONNECTOR D SUB PWB 9 SCKT 942581 RESISTOR SMR RES MF 10K 0 1 125W 25PPM 1206 106366 List of Replaceable Parts 5 Parts Lists Table 5 8 A9 Out Guard PCA cont Ref Part Des Description Number Qty RESISTOR SMR RES CERM 2K 596 125W 200PPM 1206 746461 4 57 R3 RESISTOR SMR RES CERM 2K 596 125W 200PPM 1206 746461 3 R55 R58 RESISTOR CERMET JUMPE
132. VA 200 Settling 3 to 10 seconds similar to 5700A Chassis Dimensions H x W x D 178 mm x 432 mm x 457 mm 7 in x 17 in x 18 in maximum Weight Less than 18 15 kg 40 pounds Electrical Signal Interface Fluke 5700A LP equivalent signal interface AC Mains IEEE 488 and RS 232 connectors AC power switch and Line Voltage selection all on front panel Cooling etes 1 42 cubic meters 50 cubic feet per minute ACaution Internal damage may occur if excessive external power is applied to the binding posts while the instrument is operating in current voltage or ohms In voltage and current exceeding 30 V may cause damage In ohms do not exceed the maximum specified current Introduction and Specifications 1 Specifications Accuracy Specifications DC Voltage Accuracy Absolute Uncertainty Ranges 5 C Resolution Maximum Burden output V 1 Year 0 mV to 220 mV 0 004 0 1 uV 50 Q output impedance 22 0 0025 0 0025 sov 10uv 22 0 0025 30v 0 20 0 004 100 1 Remote sensing provided on all but 220 mV range Note minimum output 0 V for all ranges DC Current Accuracy Absolute Uncertainty Maximum Maximum Inductive Ranges tcal 5 Resolution Compliance Load of output A 1 year Voltage
133. Y ARMATURE 2 FORM C 5 VDC LATCH 910773 K10 K12 x K20 K13 K17 RELAY ARMATURE 4 FORM C 5V LATCH 715078 2 5 24 List of Replaceable Parts Parts Lists Table 5 5 A6 Digital Synthesis PCA cont Ref Part Des Description Number Qty MP13 HEAT SINK ASSEMBLY WITH MJE15029 XSTR 2062805 1 MP14 HEAT SINK ASSEMBLY WITH MJE15028 XSTR 2062797 1 P107 CONNECTOR DIN41612 TYPE C RT ANG 64 807800 2 P207 PNP PWR CENUS6 TRANSISTOR SI PNP 80V 10W TO 202 495689 Q3 4 Q6 TRANSISTOR SI PNP MMBT3906 40V 200MA 250MHZ 225MW SOT 742684 012 Q14 23 TAPE NPN MMBT3904 SMR TRANSISTOR SI NPN 60V 350MW SOT 23 742676 7 Q20 Q 06 TRANSISTOR SI NPN 80V 10W TO 202 535468 Q41 42 FET DMOS N CH ROSA TRANSISTOR SI N DMOS FET DEPL TO 92 945050 RESISTOR METAL FOIL 0 1 0 1 1W 10PPM RADIAL BULK 2061053 RESISTOR SMR RES MF 10K 0 1 125W 25PPM 1206 106366 R17 RESISTOR SMR RES CERM 1K 1 125W 100PPM 1206 783241 18 R21 R29 R39 R43 R57 R70 71 R85 86 R140 R145 R147 R190 R209 5 5 25 57LFC AN Service Manual 5 26 Table 5 5 A6 Digital Synthesis PCA cont Ref Part Des Description Number Qty R7 RESISTOR CERMET 100 1 0 125W 100PPM 1206 TAPE 867494 17 R16 R22 RESISTOR SMR RES CERM 2K 1 125W 100PPM 1206 807172 15 R14 R25 R27 R45 R58 R66 R75 76 R83 84 R89 90 R106 R6 R15 RESISTOR SMR RES CERM 13K 1 0 1W 100PPM 0805 930164 R64 65 R8 R1
134. Y8021 Y8022 and Y8023 Contacting Em SpeclfiCatiobs t eene 1 6 General Specifications Re layan e ades Acc racy u u DC Voltage Accuracy T 1 7 DC Current EE AC Voltage 1 8 AC Voltage Distortion 1 9 AC Current ACCUEFdCy u u u nun E REINO Udo eO AG Current DIStor iiofu u u coperte pere 1 1 57LFC AN Service Manual 1 2 Introduction and Specifications 1 Introduction Introduction The Fluke Model 57LFC System Calibrator hereafter called the Calibrator is a precise instrument that calibrates a wide variety of electrical measuring instruments This calibrator maintains a high accuracy over a wide ambient temperature range and is able to test instruments in harsh environments eliminating the restriction of calibrating only in a temperature controlled standards laboratory With a 57LFC you can calibrate precision multimeters that measure ac or dc voltage ac or dc current and resistance The Calibrator operates in a similar manner to the 57XXA series calibrators Specifications are provided at the end of this chapter The Calibrator is a fully programmable precision source o
135. acy Test The specification for frequency is 100 ppm 0 01 Connect the 8508 to the Calibrator output terminals as shown in Figure 3 3 Then set the Calibrator to 2 V at the output frequencies specified in Table 3 4 Verify that the meter reads within the limits specified on the test record Calibration and Verification 3 Verification Tests FLUKE 57LFC Fc system cauenaron E INPUT SENSE 2 WIRE A 4 WIRE 0 ACV HI Q HI RD b V GUARD Frnt Fast Lo Lo wx 100000000000 m m m oA CATI 1000 apvOO6f eps Figure 3 3 8508A Connections to the 57LFC for AC Frequency Measurement Table 3 4 AC Frequency Values Frequency Value Measured Value Upper Limit 1000 Hz 999 936 Hz 1000 064 Hz 10000 Hz WT 99993 6 Hz 100006 4 Hz 57LFC AN Service Manual FLUKE 57LFC ZWEITE 571 Fc system caverator apv007f eps Figure 3 4 8508A Connections to the 57LFC for 4 Wire Ohms Table 3 5 4 Wire Ohm Values moasurea vano Done Speiinion Go LL a j Be 5 a Da 64 iy se a hem Been seso
136. ance from Reset Connect 10 100 1 and 10 Z3 resistors to OHMS SNS LO and OHMS OUT LO Set Disconnect 10 100 1 and 10 Z3 resistors from LO Reset Connect 19 O through 190 HI sense bus to SNS Set Disconnect 19 through 190 HI sense bus from SNS Reset Connect 19 190 1 9 MO and 19 74 resistors to OHMS SNS LO and OHMS OUT LO Set Disconnect 19 190 1 9 and 19 ZA resistors from LO Reset Connect 19 Z4 resistance to 19 O through 190 HI sense and source buses Set Disconnect 19 kO Z4 resistance from HI Reset Connect 190 74 resistance to 19 O through 190 HI sense and source buses Set Disconnect 190 kO Z4 resistance from HI 57LFC AN Service Manual 2 20 Table 2 8 A5 Ohms PCA Power up Fault Relay States Relay K25 K29 K30 K1 to K24 K26 to K28 K31 to K43 State on Power up or After Fault Set Disconnects A3 Motherboard PCA HIGUARD from ZGUARD Set Disconnects A3 Motherboard PCA OUT and SNS HI from OHMS HI and SNS Set Disconnects Motherboard OUT LO and SNS LO from LO OHMS LO and LO SNS 10 Undefined state do not care Undefined state do not care Undefined state do not care 2 Theory of Operation A5 Ohms PCA Tabl
137. ard SNS HI to HI SNS HI Set Disconnect A3 Motherboard PCA OUT HI and SNS HI from HI OHMS HI and SNS Theory of Operation 2 A5 Ohms PCA Table 2 7 Functional Description of A5 Ohms PCA Relays cont Functional Description Reset Connect A3 Motherboard PCA OUT LO to LO OHMS LO and motherboard SNS LO to LO SNS LO Set Disconnect A3 Motherboard PCA OUT LO and SNS LO from LO OHMS LO andLO SNS LO Reset ConnectLO SNS LO to OHMS SNS LO and LO OHMS LO to OHMS OUT LO Set ConnectLO SNS LO to COMP EXT LO and LO OHMS LO to COMP OUT LO Reset Connect 10 100 and 1 Z2 resistors to OHMS SNS LO and OHMS OUT LO Set Disconnect 10 100 and 1 Z2 resistors from LO Reset Connect 19 190 and 1 9 Z2 resistors to OHMS SNS LO and OHMS OUT LO Set Disconnect 19 O 190 0 and 1 9 72 resistors from LO Reset Connect 19 O Z2 resistance to 19 O through 190 HI sense and source buses Set Disconnect 19 Q Z2 resistance from Reset Connect 190 O Z2 resistance to 19 O through 190 HI sense and source buses Set Disconnect 190 Z2 resistance from Reset Connect OHMS SNS HI to HI SNS Set Disconnect OHMS SNS HI from SNS Reset Connect 10 O through 100 kO HI source bus to HI OHMS HI Set Disconnect 10 Q through 100 HI source bus from OHMS Reset Connect 1 Z3 resistance to OHMS and SNS HI Set Disconnect 1 Z3 resist
138. are three 3 PROC definitions for the Calibrator ZERO MAIN and DIAG The name associated with the PROC declaration is used in conjunction with the CAL START command to initiate a calibration procedure The procedure names are defined below Note that case is ignored ZERO ZERO The offset or zero s calibration procedure as described above print LFC cal_start zero MAIN MAIN The main calibration procedure as described above print LFC cal_start main DIAG DIAG The diagnostics procedure as described in that section print LFC cal_start diag Calibration Steps There are four types of calibration steps RUN INS REF and NOT Whenever a calibration procedure is running the controller may query the Calibrator to determine which of the four types of steps is currently being executed by the internal calibration engine To query the Calibrator for the calibration step type use the CAL STATE Command As described below the controller is expected to take different actions depending on the internal step type See the example below 3 3 57LFC AN Service Manual RUN print LFC CAL STATE input LFC 5 print shows RUN A run step requires no external intervention input or output it simply runs an internal function to perform some calibration operation Zero calibration is composed of an entry point followed a number of RUN steps and an END Instruction Step INS This step causes the proce
139. charges When the regulator output voltage reaches a value sufficient to again cause the over current condition the process repeats and this cyclical operation continues until the cause of the over current is removed Resistor R90 and transistor Q24 comprise a secondary over current detector set at approximately 0 5 A whose function is to protect the Regulator against a short circuit applied to the output Collector current flowing in 024 causes the voltage across Theory of Operation A8 High Voltage PCA Zener diode to increase rapidly towards a limit of 10 V This voltage is applied to the non inverting pin 5 input of U9 without filtering so that in the event of an overload no intentional delay occurs before the comparator changes state and the supply shuts down To provide a safer environment for fault finding of the 220 V amplifier the high voltage regulator outputs my be reduced to approximately 45 V by re routing the drain terminals of output transistors 022 and 034 to the 45 V regulated supplies on the Motherboard PCA This is implemented by setting switch S1 to its alternative position 1 with the switch actuator set furthest from the connector edge of the A8 High Voltage PCA The operating principles used to derive the Regulator PA output are identical to those for the PA output The PA output voltage 15 set to 188 V 375 V by low 14 V and high 14 V states respectively of contro
140. ct 10 kO Z3 resistance from HI Reset Connect SNS HI to COMP EXT and HI OHMS HI to 2 wire comp FGND Set Disconnect OHMS HI from FGND and connect COMP EXT HI to IZGRD and not to SNS Reset Connect 1 9 Z4 resistance to OHMS and HI SNS Set Disconnect 1 9 Z4 resistance from K19 Reset Connect 19 24 resistance to OHMS and SNS Set Disconnect 19 24 resistance from HI Reset Connect HI SRC to OHMS OUT HI Set Disconnect HI SRC from HI 21 Reset Connect OHMS SNS LO to COMP RES LO Set Connect COMP RES LO to RCOM1 and not to OHMS SNS LO Reset Connect OHMS SNS LO to LO CHK Set Disconnect 5 SNS LO from LO Reset Connect OHMS SNS HI to Set Connect BUFHCOMPV to HI Reset Short COMP EXT LO to COMP OUT LO Set Remove Short between COMP EXT LO and COMP OUT LO Reset Connect A3 Motherboard PCA HIGUARD to ZGUARD drive Set Disconnect A3 Motherboard PCA HIGUARD from ZGUARD 26 Reset Connect HI SNS HI to input of ZGUARD amplifier Set Disconnect HI SNS HI from ZGUARD amplifier input Reset Connect 0 Q resistor Short to OHMS OUT HI and OHMS OUT LO K20 K K22 K23 K24 K25 K K27 K28 K29 Set Disconnect 0 from and LO source M Reset Connect 0 Q resistor Short to OHMS SNS OHMS SNS LO Set Disconnect 0 from HI and LO sense Reset Connect Motherboard OUT HI to OHMS HI and motherbo
141. d through a 24 V bi directional Zener VR17 Miscellaneous Circuits On Sheet five of the A3 Motherboard PCA schematic J1 connects the digital signals from the A9 Controller card to the A3 Motherboard PCA The serial data signals form the communication path to the A6 Digital Synthesis PCA which also controls the in guard digital bus J6 is used for trouble shooting the circuitry in manufacturing and service testing Also on that Sheet is an area marked NOT INSTALLED These circuits may be used in a future version of the product Sheet 3 of the A3 Motherboard PCA schematic shows U27 a switch used to connect signals to the SMUX bus line for monitoring the A6 Digital Synthesis PCA is driven by U7 pin 12 on Sheet 5 of the Motherboard PCA schematic for connecting the output of the circuit checking the HVCOM current to SMUX CKIT can turn on a switch in U27 to connect the output of the temperature sensor h30 to SMUX 57LFC AN Service Manual 2 12 Troubleshooting Test Points When a problem occurs with the instrument operation one likely place to look is the A3 Motherboard PCA and its power supplies There are a number of convenient test points to monitor the supply voltages The test points are listed in Table 2 6 The test points can be divided into several groups general function unique out guard and fault General test points include V3BUF SUNR 5V ISUNR and 15V The V3BUF monitors the buffered s
142. d divider R14 and R15 which is across the 151 supply The input current to Q3 emitter is from R27 which in turn is connected to the output of U7 The current through R27 will be 2 mA also and will pass through Q3 to R32 to provide the 242 mV for the negative output transistor drive and sets the bias in the same way as explained above for the positive output transistor Solid state relay U30 is used to disable the amplifier when it is not being used A high on the MID CURRENT DISABLE line from the digital control circuit will turn on the relay shut off the bias current in the amplifier and put it in a dormant state The transconductance of this current amplifier is 242 mA V on the 220 mA range and 27 mA V on the 22 mA range High Current Output Amplifier 2 42 The output amplifier for the 2 2 A range is composed of U17 U59 U37 Q9 O4 Q10 Q2 Q8 and associated components This amplifier uses the T common for its ground reference This is a class A push pull output stage amplifier with 1 8 A bias in the ac mode and a class AB push pull output stage amplifier with 0 5 A bias in the dc mode The circuit topology is similar to the mid current output amplifier The output drive transistors bias current determination and differential drive are established in the same way as the mid current output amplifier Refer to the mid current output amplifier above for details of the operation Bias current for dc operation is set a
143. dards and calibration laboratories certified by local national standards organizations The following is a partial list of the services provided by most service centers e Repair and certified traceable calibration of all Fluke products e Certified traceable calibration of many non Fluke standards and calibrators Worldwide exchange of calibrator internal modules Delivery inside the U S A is typically within 48 hours Service agreements with the flexibility to suit your needs These can be a simple warranty extension or an agreement that includes on site support Calibration service agreements are also available in many areas 1 3 57LFC AN Service Manual e Training programs and seminars including laboratory metrology system applications and product maintenance e Application help and consulting including system design hardware selection custom software site evaluation and installation e Replacement parts inventory including recommended spare parts and module kits Visit www fluke com for locations and phone numbers of authorized Fluke service centers Accessories Table 1 1 summarizes the accessories available for the Calibrator Following the table is a brief description of each accessory Table 1 1 57LFC Accessories 5440 7002 Low Thermal Test Lead Set with Banana Plugs One 4 ft cable 122 cm and two 2 ft 61 cm cables 5440A 7003 Low Thermal EMF Test Lead Set with Spade Lugs
144. disconnect VMID from output disconnect VMID from OUT HI K5 Reset select external guard disconnect GUARD from SCOM Set select internal guard connect GUARD to SCOM K6 Reset select the 2 V buffer amp connect V3BUF to VMID for output Set disconnect the 2 V buffer amp disconnect V3BUF from VMID K7 Reset disconnect the A8 High Voltage PCA output disconnect OUT_220V from OUT_HI Set select the A8 High Voltage PCA output connect OUT_220V to OUT HI K8 Reset disconnect HIGUARD IGUARD from GUARD VGUARD Set connect HIGUARD to GUARD K9 Reset connect Digital Synthesis LO return connect OUT LO to RET LO Set disconnect the Digital Synthesis LO return disconnect OUT LO from A6 RET LO K10 Reset provide an internal VMID sense path connect VMID to the A6 VDIV Set normal operation disconnect VMID from VDIV K11 Reset provide an internal 220 V sense path connect OUT 220V to VMID Set normal operation disconnect OUT 220V from VMID On power up the relays are forced into a benign setting to protect circuitry and the customer Table 2 2 shows the state of the A3 Motherboard PCA relays after power up Table 2 3 shows the Motherboard relay states when in several states power up and standby Table 2 4 shows the status of control lines for all modes of A3 Motherboard PCA operation Theory of Operation Motherboard Table
145. dure to pause at the current step and an instruction is made available via the CAL_INFO command To resume the procedure a CAL_NEXT command must be issued This step is used to inform the user that some operator intervention is required such as an external connection to a measurement standard Note The CAL_INFO command is not mandatory Reference Step REF NOT A reference step like an INS step causes the procedure to pause and an instruction is made available via the CAL INFO command Additionally the controller is expected to supply a floating point number This number is typically a reference reading from an external DMM As an example the internal calibration procedure may setup the Calibrator to source 1 9 V Then a REF step would prompt the user to go to operate The controller would need to send the operate command and command an external DMM to take a reading The reading from the DMM would be sent to the Calibrator using a CAL NEXT command The Calibrator would use that value to calculate a new calibration constant and then would continue to the next step See the example below print GLFC CAL INFO input LFC 5 print shows Go to operate and measure the expected value print LFC OPER Go to operate INPUT DMM reading get measurement from DMM print GLFC CAL NEXT reading send DMM reading to LFC NOT simply means that the calibration procedure in no longer running If the controller determine
146. e 2 9 Final Relay States by Instrument State s A amp LS OM VA SJS 5 9JIM OX L ifs s A8LS 061 5 5 x 94M y 061 s s 5 S S S S X AGLS AIM t 5001 S S S S S 5 8 S X M 001 11 8 8 8 1 A8LS PM O 61 5 s s v 0761 5 sls s s x 915 IM 001 8 8 8 8 1 5 1 8 9JIM O OL 5 x A81S IM O 61 S S S S 1 S 1 S S S S x meni gez his 5 mom Dp Pi dt ales n 8 8 1 8 8 8 1 8 8 1 8 1 8 8 8 8 x AGLS OIM p 31045 2e m qp m ge P PS 1 rls t zc v 8 veris isu s se 6 6 i
147. e Description of the High Voltage Regulator The high voltage regulator circuits provides linear voltage regulation of the raw high voltage dc supplies from the Motherboard to produce the supply rails required by the 220 V amplifier output stage The positive and negative outputs may be set to zero or independently set to levels of 188 V or 375 V under firmware control The regulator has output current limit to protect both the 220 V amplifier and itself in the event of fault and applied short circuit conditions Raw unregulated dc supplies 3600 180UNR 180UNR and 360UNR having nominal values of 545 V 270 270 V and 545 V respectively are presented at connector P108 For a required PA output voltage of 375 V control lines HI LO V and ON OFF are set low 14 V so that transistors Q18 Q20 and Q17 are turned off and pin 2 of analogue switch 020 SW is connected to HVCOM The output of current source transistor 021 approx 0 8mA thus flows in resistors R241 R242 R252 and R253 and transistor Q66 021 controls the gate drive to Q66 to maintain the voltage at the junction of R241 and R242 equal to that at the output of 5 V reference U22 and the voltage at the drain of Q66 is therefore set at 379 V due to the potential divider action of R241 R242 R252 and R253 This voltage is applied to the gate of PA output transistor Q22 resulting in a nominal regulator output voltage of 375 V at the sourc
148. e Precision dual tracking 7 V references Two precision 28 bit pulse width modulated digital to analog converters DAC s A 500 kHz dual channel variable phase arbitrary waveform generator A3 V AC DC output amplifier 33 mV 330 mV 50 Q output attenuator e A0 33 V 1000 V sense divider and buffer amplifier Two ac dc averaging converters Two amplitude control loops for dual channel operation An 18 bit analog to digital A D converter with input mux and variable gain amplifier Athermocouple based temperature sourcing and measuring circuit Digital control circuitry consisting of octal latches relay drivers and a high speed serial link to the main CPU These functional blocks when used with the A8 High Voltage PCA and or A7 Current PCA provide single or dual channel ac dc V A W offset table and nonsinusoidal waveforms duty cycle temperature measuring and sourcing internal calibration and diagnostics and digital control over all the analog assemblies A brief description of each block 15 described below Precision Dual Tracking 7 V References Refer to Sheet 2 of the A6 Digital Synthesis PCA schematic The reference circuit is based on the ref amp set used in the 8842A Reference amplifier and op amp 038 along with Z3 and Z4 generate a trimmed 7 V reference This reference is inverted by a flying capacitor inverter circuit consisting of U76 C60 and C74 and buffered by U27 Each r
149. e a detailed description and analysis where appropriate of the printed circuit board assemblies PCAs used in the 57LFC System Calibrator The Calibrator contains the following PCAs LED PCA A3 Motherboard A5 Ohms e A6 Digital Synthesis A7 Current PCA e A8 High Voltage e A9 Out Guard CPU See Figure 2 1 for a block diagram of the 57LFC System Calibrator 2 3 57LFC AN Service Manual A9 Outguard A6 Controller Inguard IEEE488 Controller RS232 A3 Mains Outguard Trans Power former 12 V 5 A6 Digital Synthesis amp Reference 0 to 2 2 V A3 T Output Binding Switch Posts Inguard Power 15 V 5 6 V A5 OHMS 0to 19 MQ A7 Current Oto 2 2 A AC DC A8 High Voltage 2 to 220 V AC DC Figure 2 1 57LFC Block Diagram apv101f eps Theory of Operation 1 LED A1 LED PCA The Calibrator front panel Al LED PCA provides the only visual indication of the instrument operation These LEDs provide a color coded scheme for the instrument status AN Warning This instrument is capable of outputting lethal voltages Observe all safety precautions While the LEDs should provide years of operation they are subject to wear out like any other component Never touch the bindin
150. e amplitude accuracy test verifies the accuracy of dc voltage at the Calibrator front panel output terminals Use the specifications in Chapter 1 to determine maximum load for testing Connect the equipment as shown in Figure 3 1 and verify the Calibrator is within the limits shown in Table 3 2 FLUKE 57LFC WEISE system OPERATE STANDB 8508A SENSE FLUKE 8508A FEFERENCE MULTIMETER a POW LI In Frnt Fast 100000000000 004 Figure 3 1 8508A Connections to the 57LFC for DC Volts Measurement 57LFC AN Service Manual Table 3 2 DC Volts Measurement Limits ma eos 2 2 2 e 2 bos w semen m x m ms m fa s Lm Lm Calibration and Verification 3 Verification Tests AC Voltage Tests AC Voltage Accuracy Test The ac voltage amplitude accuracy test verifies the accuracy of ac voltage at the Calibrator front panel terminals First use the 57204 to characterize all the points in Table 3 3 Next connect the equipment as shown in Figure 3
151. e it is converted into digital value to be read by the micro controller Fault Detection Refer to Sheet 7 of the A6 Digital Synthesis PCA schematic In order to minimize damage caused by misuse abuse component malfunction or software errors a fault detection circuit was incorporated into the Calibrator It consists of a set reset fault latch a power MOSFET for driving reset coils and various fault detecting comparators On the A6 Digital Synthesis PCA the only kind of faults detected are destructive voltages present at the instrument output during voltage mode operation This type of fault is detected with a window comparator U50 that monitors the output of the sense buffer U21 When the output U21 exceeds 10 V the output of U50 goes low setting the fault latch U16 The output of the fault latch sets the signal CLR DRVR hi disabling all the latching relay drivers and turns on Q6 which resets all the latching relays connected to REL RST The fault latch also signals the FPGA of a fault condition via the FAULT signal allowing the software to respond appropriately In the case of the DDS assembly a fault condition disconnects all DDS relays that are connected to the output Theory of Operation 7 Current The FAULT REL RST and CLR DRVR signals are also routed to the A3 Motherboard PCA allowing any other assembly to detect and respond to any abnormal conditions as needed Digital Control Refer to She
152. e terminal of the device Resistors R38 R41 to R43 R76 R78 R81 and R84 form a potential divider chain which sets the gate and consequently source voltage of Q7 at approximately half way between the voltages at the 360UNR input and the Regulator output VR3 VRS VR6 and VR7 do not conduct as the sum of their breakdown voltages exceeds that appearing at this node in normal operation and Q18 is turned off The Regulator input output voltage difference and consequently output device power dissipation is thus shared equally between Q7 and Q22 allowing higher input voltages and output currents than if a single output device were used In this mode diodes CR11 and 12 are reverse biased to prevent current flows from 1800 raw supply Zener diodes VR9 and 2 49 57LFC AN Service Manual 2 50 10 are included to restrict the regulator output voltage if Q66 or any of it s associated components fails For a required output voltage of 188 V control line HI LO V 1 set high 14 V and ON OFF is set low 14 V Transistor 018 is thus turned shorting Zener diodes VR5 VR6 and causing diode VR3 to conduct via resistors R38 and R41 to R43 The gate and consequently source of Q7 are thus held at approximately 150 V As this is lower in voltage than the 180UNR input supply diode 13 is reverse biased and all regulator input current flows from the 1800 supply via CR12 into the drain te
153. e value of the same magnitude as the input As the input voltage begins to decrease U20 will turn off and leave C59 with a voltage equal to the negative of the peak input voltage C59 charges quickly through U20 and discharges slowly through R193 and R170 after U20 shuts off U20 has an open collector output stage The voltage across C59 15 applied to the positive input of one op amp in U19 The negative input is connected to Zener diode VR2 5 1 V that is connected between the op amp output and the negative input VR2 1s biased on by R108 and by R63 when solid state relay U45 is on With this circuit configuration the output of the op amp will always be 5 1 V lower than the voltage on the positive input With 0 V compliance the voltage across C59 will be 0 and therefore the output of U19 will be 5 1 V With 6 V compliance the voltage across C59 will be 6 V and therefore the output of U19 will be 11 1 V The output of this op amp is the IREF that is supplied to the high current power supply on the A3 Motherboard PCA The other half of U19 is configured as a unity gain inverter and inverts the IREF to generate the IREF signal for the high current power supply At power ON solid state relay U45 will be off and the bias current to VR2 and C57 which is in parallel with VR2 must come R108 200 The output signals IREF and IREF will therefore rise slowly and in turn the high current power supply will come up slowly After a delay
154. eference 15 also buffered by a discrete output stage Q4 amp 05 Precision 28bit PWM Dual DAC s Refer to Sheet 2 of the A6 Digital Synthesis PCA schematic Since the two precision DAC s are identical only the voltage channel DAC will be described This DAC design uses pulse width modulation PWM to convert a digital value to a precise analog voltage The duty cycle is generated by programmable counter logic contained in FPGA U5 The counters are 14 bit binary operating off of the 10Mhz clock generating a variable duty factor pulse train at a frequency of 610 3515Hz The duty cycle has a resolution of 1 part in 16384 14bits This variable duty cycle is complemented and deskewed by a D flip flop and outputted from the FPGA as DACIPREF and DACINREF driving the gate pins of a quad analog switch U45 045 alternately connects the input of the DAC filter 210 to the 7 V references The output of this filter which consists of Z10 R75 R76 U28 and C76 78 will have a voltage equal to the average value of the voltage at its input VDC D 5 14 and D N 16384 where is the value that the timer is programmed to 2 33 57LFC AN Service Manual 052 and Z10 are used to cancel the resistance of U45 while U58 and Z2 buffer the output and divide it by two To obtain an additional 14615 of resolution another PWM channel is generated and output at U18 12 This signal is inverted by U19A divided by 70 R72 and R73 and s
155. elay States by Instrument State cont nm 1 8 85 8 8 8 5 8 8 58 8 s s x dao o1 xH Z F 8 1 2 81 8 1 2 91915 isu 8 v 8 4 0 6 6 cM S S 4 1 VM EM 6 S 0 L 2 0 v 6 1 9 wl wt 0 8 9 9 gt cM M IM 1 24 27 17 20 24 24 64 64 lt 24 24 63 DM 9 A tA 87 ATHO enua 2 25 57LFC AN Service Manual Other Control Circuits Other controls on the A5 Ohms PCA are used for selecting a number of different parameters Table 2 10 lists the name of the other control signals and provides a functional description The control signals are driven by U39 and U35 as shown on Sheet 4 of the 5 Ohms schematic Table 2 10 Functional Description of Signals Signal Functional Description ENCOMPFAULT Connects the divided and buffered SNS HI compliance voltage to the circuit that will pull down the INS HI line if the voltage exceeds 33 5 V when asserted Low CKEXTRA Not used CKCOMPV Connects the divided and buffered SNS voltage to the SMUX line when asserted Low CKLO Connects the LO output f
156. ent into Standby 2 27 2 28 57LFC AN Service Manual Table 2 11 Compliance Voltage Thresholds Max Vcompliance Max BUFHCOMPV Output Resistance V dc V dc SMUX Limit V dc 00 0 0 0 010 1 0 Q 0 14 0 047 0 05 1 9 Q 0 28 0 093 0 10 100 0 14 0 047 0 05 190 0 28 0 093 0 10 1000 1 41 0 47 0 5 1900 2 83 0 94 1 00 10 2 83 0 94 1 00 1 9 4 24 1 413 1 50 10 14 14 4 714 5 00 19 7 07 2 357 5 00 100 14 14 4 714 5 00 190 14 14 4 714 10 0 1 0 28 28 9 427 10 0 1 9 MQ 28 28 9 427 10 0 10 M 28 28 9 427 10 0 19 28 28 9 427 10 0 Theory of Operation A5 Ohms PCA Diagnostics Diagnostics which may be executed as a remote command check that the relays are working and that each of the resistances is close to its calibrated value If problems are found an error message is printed The error messages can be found in Appendix A of the 57LFC AN Operators Manual Table 2 12 lists a few of the relay settings after a power up Ohms diagnostics work as follows for each resistance in turn Sets the relays see Table 2 8 ORLY to the DIAG state for the resistance desired e Set the OTEST register for the test current desired based on Table 2 14 SettheI ACDC DDS output voltage to be that for the proper test current shown in the Table 2 14 e Set the OCHK register see Table 2 13 to the DIAG state for measuring Ivref and measure the SM
157. enue 15 15 06 Ue Square 239920 Singapore Parts Lists The following tables list the replaceable parts for the 57LFC System Calibrator Parts are listed by assembly and alphabetized by reference designator Each assembly is accompanied by an illustration showing the location of each part and its reference designator List of Replaceable Parts 5 Parts Lists Table 5 1 Final Assembly Des Description Number Qty mz scwwowscessemom meos 2 23 4 SCREW 10 32 MODIFIED SCREW 10 32 MODIFIED CONNECTOR ACCESSORY D SUB JACK SCREW 4 40 250 LW FLAT 1777348 H WASHER LOCK SPLIT STL 255 491 062 LOCK SPLIT STL 255 491 062 111518 POWER ENTRY MODULE LINE FILTER A C INLET ON OFF SWITCH 1 2065010 POLE 4A 250VAC BULK POWER ENTRY MODULE CUSTOM FUSE DRAWER MARKINGS 100 2065022 208 230 BULK OUTPUTBLOCKDECAL BLOCK DECAL 2100381 E 57LFC AN Service Manual Table 5 1 Final Assembly cont me Des Description Number Qty List of Replaceable Parts 5 Parts Lists CAUTION SUBJECT TO DAMAGE BY STATIC ELECTRICITY A6 H4 MP9 A5 H4 6 H134 PL H5 4 PL 4 PL H42 PL MP2 2 PL H1 4 PL H1 4 PL H2 H2 4 PL MP4 H1 2 PL SG upto an 5 apvO50f eps Figure 5 1 Final Assembly 5 7 57LFC AN Service Manual BLUE WIRE FROM TRANSFORMER w3 H2 2 PLACES
158. er K13 4 ST ES 10 K13 K13 9 4 13 ka A29 K25 8 9 X RS ST 1281 bsar n 1 95 C29 HIGUARD 4 we i3 2 6 11 65281 ZGUARD 23 Ln DS4E XX DS2ET2 K5 10 14 RS DSAE 12 100 7 KS OPA129 k psan 1 REFERENCE DESIGNATON ee CR13 CR9 Geen NOT USED BAV199 k gt Ye mj m one C50 61 62 70 CR12 14 P1 104 106 204 R24 29 32 39 62 3 v osaid __ 10 K10 K34 RST 14 RS 1 z DSAE 13 11 8 K32 RS 9 Kaz 1P ik LO SNS LO OHMS SNS LO ST 4 LO OHMS LO OHMS OUT LO amp XX DS4E 3 COMP EXT LO CET 57LFC 1005 LO 1 of 5 COMP OUT LO 2 Figure 6 3 A5 Ohms PCA cont 6 12 Schematic Diagrams 6 8 7 6 5 4 3 l 2WIRE COMPENSATION CIRCUITRY HI COMP C23 0 19 10U 7T 25V U19 U20 TLC2652AC AA COMP EXT HI BUF634T AAA R14 4 0 22 4 COMP OUT HI CET 10 100 TO220HS Ld 0 047U 10 0 C40 0 1U T LO COMP CD COMP
159. er the sensor The output of the sensor goes through a RC low pass filter and is sent through 010 to the SMUX line where it can be periodically monitored when in the 2 2 A range An out of range condition would indicate some kind of circuit failure or a blocked or failed fan High Current Amplifier Power Supplies Mongo Supplies The power supply for the 2 2 A high current amplifier was designed to have a magnitude 5 V higher than the output peak compliance voltage The supply will therefore be 5 V with 0 V compliance and 11 V with 6 V peak 4 V rms compliance The circuitry used to detect the peak compliance voltage is composed of U16 U21 U20 019 and U47 and associated components U16 is a unity gain buffer that monitors the output voltage from the current PCB on the OUT line through K19 and R114 The output of U16 is switched by U47 to the input of U21 U21 is configured as a full wave rectifier which gives a positive rectified output for either polarity of the input signal This rectified output is filtered by R169 C58 and then applied to switch U47 where it is switched to the PMUX line PMUX is monitored by the A6 Digital Synthesis PCA which generates the compliance voltage exceeded message and places the instrument back to standby The output of full wave rectifier U21 is also applied to a track and hold circuit composed of U20 C59 R170 and R193 The positive input signal from U21 is inverted and charges C59 to a negativ
160. ese amplifiers have gains of 10 and 100 for the 22 V and 220 V ranges respectively The exact gain of each amplifier is not critical as overall amplitude control is maintained by an outer amplitude control loop external to the A8 High Voltage PCA However this outer loop does not correct for distortion noise or offset all of which must be suitably controlled within the amplifiers Both amplifiers are directly dc coupled to the output terminals and protection against short circuit is provided by appropriate output stage current limit circuits The A8 High Voltage PCA also contains a dual polarity high voltage regulator circuit which serves to isolate the 220 V amplifier from raw dc supply voltage variations resulting from mains fluctuations transformer regulation and ripple The magnitude of the positive and negative outputs may be independently set under firmware control to levels of 188 V or 375 V as dictated by the required amplifier output thus allowing amplifier output device dissipation to be reduced The regulator also contains a current limit and over current shutdown feature to further protect the 220 V amplifier in the event of an output short circuit See Figure 2 7 a diagram of the A8 High Voltage PCA 22 V and 220V amplifier 2 Theory of Operation A8 High Voltage PCA 19110Au0 2 5064 inven 1 526915 Indino pue GINA
161. et 8 of A6 Digital Synthesis PCA schematic The inguard analog circuitry is controlled through an FPGA U5 U5 contains a 1 megabit s serial link a serial to parallel shift register and a state machine to provide a microprocessor style data address and control signals U5 also incorporates six PVM circuits for DAC s and a two channel DDS circuit with phase adjust and phase error measurement There are also some general purpose registers for control of the analog circuitry A7 Current PCA Figure 2 4 shows the operation of DC current functions The DC input signal to the A7 Current comes from Digital Synthesis on the ACDC The signal 15 generated by a high resolution digital to analog converter IDAC buffered by amplifier U58 divided by Z1 and applied to the positive input of amplifier U9 The output of U9 is the I ACDC signal The negative input of U9 is connected to the IFBK line which is the feedback from the shunt amplifier on the A7 Current In operation the IFBK signal must be equal to the IDAC OUT signal If it is not equal the output of U9 changes the I ACDC signal to adjust the A7 Current PCA output to make them equal The ACDC signal is switched by 025 to provide ACDC SW input to U18 The output of U18 is buffered and applied to one of the three transconductance output amplifiers The low current amplifier provides the 220 and 2 2 mA ranges The mid current amplifier provide
162. f Q53 which would otherwise occur under overload conditions 2 47 57LFC AN Service Manual 2 48 The output from the collector of Q53 is fed via common gate connected high voltage P channel mosfet Q52 to the collector base of Q51 Q52 is necessary to isolate the collector of Q53 which is a low voltage small signal device from the high voltage associated with the PA supply rail 051 forms the input of a current mirror whose output flows into the collector of Q50 The output input current ratio of this mirror is defined essentially by the ratio of the values of R198 and R118 and is approximately 4 7 The collector of Q50 is isolated from high voltage signal excursions by common gate configured N channel mosfet stage Q33 and at low frequencies the mirror output current almost entirely flows via the drain of this device The gate of Q33 is referenced to the PA supply rail via VR18 and the drain of this device provides the full output voltage swing of the amplifier Drain bias current for Q33 is supplied by a current source comprising 047 Q48 CR46 and R194 thus maximising the low frequency current to voltage gain of the stage this current is set at approximately 8 mA Common base stage Q30 is included to recover mirror output current which would otherwise be lost via the drain gate capacitance of Q33 at high frequencies This 15 necessary to prevent loss of gain and to alleviate distortion caused by variations of drain gate capacitance with
163. f the following e DC voltage to 220 V AC voltage to 220 V rms with output available from 10 Hz to 100 kHz AC and DC current to 2 2 A with AC output available from 10 Hz to 20 kHz Resistance in values from 0 Q to 19 in and 1 9x Features of the calibrator include the following e Automatic meter error calculation obtained through using a simple remote adjust Programmable entry limits used for restricting the levels that can be remotely keyed into the calibrator preventing access to levels that may be harmful to equipment or personnel e Real time clock and calendar e Offset and scaling modes that simplify linearity testing of multimeters Standard IEEE 488 GPIB interface complying with ANSI IEEE Standards 488 1 1987 and 488 2 1987 Internal self testing and diagnostics of analog and digital functions e Status LEDs on front panel to indicate standby yellow operate green high voltage red and fault red and yellow Service Information Each calibrator is warranted to the original purchaser for a period of one year beginning on the date received The warranty is located at the front of this manual Service and technical advice for the calibrator is available at Fluke Service Centers For a complete list of Fluke Service Centers visit www fluke com A worldwide network of Fluke service centers supports Fluke instruments and assists customers in many ways Most service centers have stan
164. fore connecting anything to any of the 57LFC terminals A protective ground connection by way of the grounding conductor in the power cord is essential for safe operation Use the Proper Power Cord Use only the power cord and connector appropriate for proper operation of a 57LFC e Useonly a power cord that is in good condition Refer cord and connector changes to qualified service personnel Do Not Operate in Explosive Atmospheres To avoid explosion do not operate the 57LFC in an atmosphere of explosive gas Do Not Remove Cover To avoid personal injury do not remove the cover from the 57LFC Do not operate the 57LFC without the cover properly installed There are no user serviceable parts inside the 57LFC so there 15 no need for the operator to ever remove the cover SERVICING SAFETY SUMMARY FOR QUALIFIED SERVICE PERSONNEL ONLY Also refer to the preceding Operator Safety Summary Do Not Service Alone Do not perform internal service or adjustment of this product unless another person capable of rendering first aid and resuscitation 15 present Use Care When Servicing With Power On Dangerous voltage exist at many points inside this product To avoid personal injury do not touch exposed connections and components while power is on Whenever the nature of the operation permits keep one hand away from equipment to reduce the hazard of current flowing through vital organs of the body Do not wear a grounded wrist
165. g posts without first checking the output with a multimeter The front panel A1 LED PCA is connected to and controlled by the A3 Motherboard cable is used to connect the Motherboard to the Al LED PCA On power up the yellow LED will light indicating that the instrument has moved into a standby state The green LED is used to indicate that the instrument is in operate and there may be live voltages on the binding posts The red LED is used to indicate that the instrument may be outputting hazardous voltages greater than 30 V rms If diagnostic failures occur during power up both the yellow and red LEDs light If all three LEDs are lit the instrument is broken and must be sent to a qualified technician for repair A3 Motherboard PCA The following discussion covers the theory of operations for the A3 Motherboard PCA circuits This Motherboard generally carries power as well as system signal buses to the circuit cards The A3 Motherboard PCA can be divided into several areas 1 relay control and switch matrix 2 LED control and output cables 3 analog and digital buses 4 low volt buffer 5 in guard power supplies 6 out guard power supplies 7 miscellaneous circuits and 8 list of fuses Please refer to the A3 Motherboard PCA schematics for this discussion AN Warning The A3 Motherboard PCA contains lethal voltages Only qualified technicians should do troubleshooting Relay Control and Switch Matrix
166. ge difference between the Amplifier output and power supply rails 15 supported almost entirely by Q1 Q2 Q25 and Q29 the bulk of the amplifier output stage power dissipation 15 liberated in these in devices Transistor Q26 provides limiting for positive output currents by absorbing further increases in gate source voltage of Q4 once sufficient voltage is developed across the R105 to turn Q3 on Q6 provides limiting for negative currents in a similar manner by restricting the gate source voltage of Q2 The overall gain of the amplifier within the specified operating bandwidth is defined by feedback network R125 R127 and R132 and is given the expression R125 R127 R132 Stability is ensured by dominant pole compensation provided by local feedback from the emitter of Q46 to the base of Q50 via capacitor C48 Additional open loop frequency response shaping is provided by local feedback around U3 U4 R281 and C29 Fuse F2 is included to provide limited protection in the event of an external high voltage source being connected to the output terminals This device is connected within the overall feedback loop of the Amplifier to minimise distortion particularly at low frequencies resulting from the non linear characteristic of the device Theory of Operation A8 High Voltage PCA The amplifier output 15 routed to connector P108 via fuse F2 resistors R183 and R185 chokes L2 and L2 and relay K1 R183 R185 L2 and L2 are inc
167. he loop integrator it 1s first converted to a dc voltage by an average responding ac dc converter U40 U20 Q2 Q3 5 039 This dc voltage is filtered and buffered by 084 and U3 and switched into the loop integrator by U15 As in dc the loop integrator reference pin has the VDAC signal on it The difference between the VDAC and the output of the averaging converter is integrated and applied to the DDS DAC IREFIN pin This adjusts the output voltage of the DDS DAC 013 until the difference is zero DC Current Operation Refer to Sheets 2 and 4 of the A6 Digital Synthesis PCA schematic In all the dc current ranges the output from 21 is applied to the noninverting input of the control loop integrator U9 The output of U9 is switched to I AC DC by U33A This signal is converted to a high impedance current source by the transconductance amplifier on the A7 Current PCA This current is routed to the AUX HI output and flows through the UUT returning into AUX LO terminal It then passes through a shunt on the 7 Current PCA converting it back into a voltage I FBK I is switched to the inverting input of U9 by U31 which integrates the difference between its two inputs forcing them to be equal AC Current Operation In all the ac current ranges the second DDS channel from U34 1 switched to I ACDC by U33C This signal is converted to a current outputted and fed back on I FBK the same way as for dc currents In AC I FBK is swi
168. ibrator To clean the air filter 1 Disconnect line power 2 Remove the filter by pulling the filter s retainer downwards it hinges at the bottom and removing the filter element 3 Clean the filter by washing it in soapy water Rinse and dry it thoroughly before reinstalling 4 Reinstall the filter Figure 4 2 Accessing the Air Filter Maintenance Cleaning the Air Filter 4 4 5 57LFC AN Service Manual 4 6 Replacing PCA Modules Follow the steps below to replace PCA modules in the Calibrator Refer to Figure 4 3 for a disassembly illustration and the location of the PCA modules 1 Turn the Calibrator off and disconnect line power 2 Remove the six screws holding the top cover in place Remove the top cover 3 Remove the two screws holding the guard cover in place Tilt the guard cover up and leave vertical or remove the guard cover 4 Remove the required module using the module extractors Guard Cover apv102f eps Figure 4 3 Exploded View of the Calibrator Maintenance Cleaning the Exterior Cleaning the Exterior To keep the calibrator looking like new clean the case using a soft cloth slightly dampened with either water or a non abrasive mild cleaning solution that is not harmful to plastics ACaution Do not use aromatic hydrocarbons or chlorinated solvents for cleaning They can damage the plastic materials used in the Calibrator
169. ignal used for ac and dc output voltages between 220 mV and 2 2 V SUNR 5 15 and 15V monitor the main supplies used in all of the in guard board circuitry Power supplies unique to the A7 Current PCA are monitored MMONGO MMCOM IREF ICOM 151 and 151 Power supplies unique to the A8 High Voltage are 45UNR 45V 180UNR and 3600 High Voltage uses the 45V 180UNR and 360UNR to produce the high voltage outputs The A5 Ohms uses the general and 45Vsupplies Out guard test points monitor provide access to 5VG UNR 5VG GGND 12 UNR and 12VG power signals These power supplies are only used for the controller card A9 and for manufacturing test fixtures Besides monitoring the power supplies several test points are used to monitor fault conditions Note that the FAULT signal is a wired The main fault signal 15 If any fault occurs becomes active TP2 monitors the 15V BALANCE FAULT signal and provides status on the 15 V and 15 V supplies If either supply varies from the other by too much indicating excessive load or failure the fault becomes active TP4 monitors the HVCOM signal trace If the HVCOM signal moves more than 0 5 V from SCOM the fault becomes active TP5 monitors OVER22V This signal indicates if SCOM differs from chassis ground by more than about 23 V TP49 monitors 45 V BALANCE FAULT This fault
170. imum load 440 for 50 mA to the dc voltage output when set to 21 9 V dc using 8508A to measure Verify that the voltage is at the correct limit e Apply the maximum load 440 2 to the ac voltage output when set to 100 kHz and 21 9 V rms using 8508A to measure Verify that the voltage is at the correct limit Apply the maximum load 11 for 20 mA to the dc voltage output when set to 219 V dc using 8508A to measure e Verify that the voltage is at the correct limit 57LFC AN Service Manual Apply the maximum load 11 to the ac voltage output when set to kHz and 219 V rms using 8508A to measure e Verify that the voltage is at the correct limit FLUKE 57LFC gt 57 SENSE 4 00000000 apv012f eps Figure 3 9 8508A Connections to the 57LFC for Voltage Compliance Testing Table 3 10 Voltage Output Compliance Limits 3 18 Calibration and Verification 3 Verification Tests Harmonic Test Levels for AC Volts The harmonic ac voltage test verifies that the output ac signal has a limited amount of noise in the signal For these tests the use of the distortion analyzer or spectrum analyzer 1s required Follow the vendor s specifications for setting up those instruments The connection used will depend on which test instrument is used Figure 10 shows the set up used for a Booton 1130A and Agilent
171. ion testing 3 5 57LFC AN Service Manual Table 3 1 Recommended Equipment for Calibration and Verification Recommended Equipment Recommended Model Calibration and Verification Chapter 3 of the 57LFC AN Define procedure test points and Procedure Service Manual specifications Test Lead Kit Fluke 8508A LEAD or equivalent Cable interconnect assembly 8 1 2 digit DMM Fluke 8508A DMM or equivalent Measure DC Volts DC Current AC Volts AC Current and Resistance Precision Calibrator Fluke 5720A or equivalent Characterize 8508 for ac voltage and ac current measurements Harmonic Distortion Analyzer Boonton 1130 or equivalent Measure LF harmonic distortion of ac voltage and current Harmonic Distortion Analyzer Agilent ESA 4411A Spectrum Measure harmonic distortion of ac Analyzer or equivalent voltage for f gt 30 kHz Test Controller Computer with an IEEE 488 Connect to and communicate with interface card or equivalent the Calibrator Frequency Measurement Fluke 8508A or counter with 10 Hz to 100 kHz frequency range and 25 ppm frequency uncertainty or equivalent Shunt Resistors 5 1 8 watt 0 1 1 W 10 100 and 1 k Harmonic testing for AC current unless noted Load Resistors 10 1 8 10 W 40 0 1 W 440 2 W Compliance testing and 1k 5 W and 22 k 5 W Resistor Divider 1096 1 4 W 2 M 20 k Harmonic Testing Calibrator Configuration and Pre check The Calibrator must be switched on and powered for at least 30 minutes pr
172. ior to verification testing and the air filter inspected for adequate airflow Refer to filter inspection and cleaning procedure provided in Chapter 4 for detailed cleaning instructions Verification can only be performed using a controller as the Calibrator has no front panel controls Furthermore the Calibrator has no internal hardware adjustments When powered correctly the Calibrator front interface panel STANDBY LED indicator will illuminate yellow When in operate the OPERATE LED will illuminate green If the output voltage goes above 30 V the warning LED will illuminate red If the unit encounters an output fault both the yellow and red LEDs will light For example if in current mode and the load is removed a fault condition will be indicated since the output compliance voltage will go to a maximum value Self test routines are executed at power up that test the internal controller device and memory Any failure at power up will be displayed with both the yellow and red LEDs lighting A failure message can be requested over the IEEE 488 bus as part of the instrument status see Chapter 3 in the 57LFC AN Operators Manual for additional information Calibration and Verification 3 Verification Tests Confirm Cal Enable J1 is in the disabled condition before starting the rest of the verification procedures If the unit passes all tests Cover the Cal Enable switch with a calibration label DC Voltage Test The dc voltag
173. l line and is set to zero when the ON OFF assumes it s low 14 V state Note that ON OFF and ON OFF lines are derived from the same control signal and therefore the and PA outputs cannot be set to zero independently Heat Sink Temperature Measurement The temperature of the heatsinks for 220 V amplifier output devices Q25 Q29 and high voltage regulator output devices Q22 and Q42 are monitored by heatsink mounted integrated circuit temperature sensors U25 U26 U27 and U28 The sensor output voltages are multiplexed onto the SMUX line by U19 via U10 for subsequent A to D conversion Digital Interface and Control The digital interface to the A8 High Voltage PCA comprises an 8 bit data bus lt 7 0 gt three address lines ID ADDRO ID ADDRI and ID ADDR2 a board select line CSO and a write line When the board select line is low U7 routes the IG WR signal which is normally held high to the clock inputs of 4 bit relay drivers U12 and U13 or one of two 8 bit latches 014 and 017 as determined by the state of the three address lines 8 bit data is clocked into the latching inputs of U12 and U13 which are connected to act as a single 8 bit device 014 or U17 in response to the WR line being taken momentarily low data being latched on the low to high transition The open collector outputs of U12 and U13 are grouped in pairs each pair driving the set and rese
174. le of the AC input When transistor Q9 is on the negative rectified voltage will charge C53 which provides the MMONGO output U24 and Q17 control Q9 The inputs to U24 are the IREF on input and the full wave rectified ac on the negative input If the IREF signal is more negative than the AC input signal the output of U24 will be negative which will turn on 017 With 017 on the 151 supply voltage will turn on Q9 Once Q9 15 it will remain on until C53 is charged up to a voltage equal the IREF signal and then Q9 will be turned off by U24 Q17 The voltage at the negative input of U24 turns the output off which turns off Q17 and Q9 If Q9 is off diode CR37 which is connected between the negative input of U24 and the negative supply output will begin to conduct when the AC input is one diode drop less than the negative supply output If the negative supply output increased more than one diode drop from the IREF 024 017 will turn on which will turn Q9 on and allow C53 to charge for more of the AC input cycle rather then waiting for the next cycle of the AC input A8 High Voltage PCA 2 44 The function of the A8 High Voltage PCA is to amplify the 2 2 V nominal max signal from the A6 Digital Synthesis PCA to the output levels required for the 22 V and 220 V ranges The A11 Isothermal PCA 15 assembled and tested as part of the A8 High Voltage PCA This is accomplished by employing separate amplifiers for each range Th
175. le on the front panel The fuse rating label to the right of the fuse holder shows the correct replacement fuse rating for each operating voltage To check or replace the fuse 1 Disconnect line power 2 Insert a small screwdriver in the fuse holder release slot and push upward until the fuse compartment pops free See Figure 4 1 3 Slide the fuse and fuse holder out of the fuse compartment 4 Inspect or replace the fuse Install the fuse compartment in the calibrator 4 3 57LFC AN Service Manual CAUTI i run La MARON 1 TE m mm RE m Hear F ge Eds W TING Wary NING Pa oA Corp MUECTON BE NJ faron Ji enamaron stanppy A output N SENSE vn J2 SERIAL 2 Mx SERIAL1 9 pyr v GUARD T IEEE 488 J4 C DO000000000000000000000000000000 00000000 00000 00000 apw004f eps Figure 4 1 Replacing the Fuse Cleaning the Air Filter A ACaution Damage caused by overheating may occur if the area around the fan is restricted the intake air is too warm or the air filter becomes clogged The air filter must be removed and cleaned at least every 30 days or more frequently if the calibrator is operated in a dusty environment The air filter is accessible from the rear panel of the Cal
176. lowed and test uncertainty ratios are kept above 3 1 automation of the verification test will meet the requirements of verifying the product specifications AN AWarning This instrument is capable of outputting lethal voltages Observe all safety precautions To avoid shock the operator should not electrically contact the Output V or Sense binding posts during operation Lethal voltages of up to 230 V ac or dc may be present Whenever the nature of the operation permits keep one hand away from the equipment to reduce the hazard of current flowing through vital organs of the body The verification tests are sufficient to insure that the shipped units will meet and or exceed published specifications over the specified environmental conditions and specified calibration interval tests limits are based on specifications measured within 23 C 3 room temperature and humidity less than 80 Any test that fails will be rerun immediately If the failure repeats it will be noted as a failure and testing will continue with the next step 1f possible Failures will be repaired and then the unit will be retested Test Equipment The equipment listed in Table 3 1 is for reference only You can substitute any of the equipment provided adequate measurement accuracy with a test uncertainty ratio of 4 1 if possible Only equipment that 15 calibrated and traceable according to the manufacturer specifications may be used for performance verificat
177. luded to help prevent output stage instability in the presence of capacitive loads Op Amp 015 transistors 013 and Q61 and resistors R49 R94 and R97 comprise precision current mirror whose output from the collectors of Q13 and Q61 is proportional to the current flowing from the PA supply into the output stage The input output ratio of the mirror is defined by the ratio of R49 to the parallel combination of R94 and R97 and is set at a nominal value of 110 1 Low pass R C network R235 and C65 restricts the bandwidth of the signal fed to U15 and Darlington connected transistors Q14 and Q62 increase the output voltage capability of the mirror to accommodate the supply The mirror output is sensed by resistor R58 and C67 is included to provide low pass filtering so that at high frequencies the resultant voltage represents the average output stage current Dual FET input operational amplifier U2 diode CR65 capacitor C92 and resistors R264 and R277 comprise a peak detector circuit that senses the voltage developed across R58 and temporarily holds its peak value This ensures that at low frequencies the peak value of current which is more representative of output device dissipation than the average is sensed The peak detector output is multiplexed onto the SMUX line via U10 for subsequent A to D conversion The current from the PA supply into the output stage 15 monitored in a similar manner to that from the PA supply Detailed Hardwar
178. may find the following booklet prepared by the Federal Communications Commission helpful How to Identify and Resolve Radio TV Interference Problems This booklet is available from the U S Government Printing Office Washington D C 20402 Stock No 004 000 00345 4 OPERATOR SAFETY SUMMARY ANWARNING HIGH VOLTAGE is used in the operation of this equipment LETHAL VOLTAGE may be present on the terminals observe all safety precautions To avoid electrical shock hazard the operator should not electrically contact the output hi or sense hi binding posts During operation lethal voltages of up to 2200 V ac or dc may be present on these terminals Whenever the nature of the operation permits keep one hand away from equipment to reduce the hazard of current flowing thought vital organs of the body Terms in this Manual This instrument has been designed and tested in accordance with the safety standards listed in the General Specifications which are located in Chapter 1 of this manual This manual contains information and warnings which have to be followed by the user to ensure safe operation and to retain the instrument in safe condition A AAWARNING statements identify conditions or practices that could result in personal injury or loss of life A AACAUTION statements identify conditions or practices that could result in damage to the equipment or other property Symbols Marked on Equipment Caution risk of electric shock
179. o be 0 0196 of frequency setting 1 8 Introduction and Specifications 1 Specifications AC Voltage Distortion Max Distortion and noise Ranges Frequency 10 Hz to 10 MHz Bandwidth output V OmV to 22 mv 22 mV to 220 022 220 22 Vt022V 22710220 1 For larger resistive loads multiply uncertainty specifications by actual load maximum full load for accuracy 1 9 57LFC AN Service Manual AC Current Accuracy Absolute Uncertainty Maximum Maximum Ranges Frequency tcal 5 Resolution Compliance Inductive of output A 1 year Voltage rms Load 30 pA to 220 pA 001 pA 50 uH 022 mA to 2 2 mA dd 100 WA 1 400 pH with inductive compensation ON 2 See AC Current Compliance Adder and Distortion Table for impact of compliance voltage on specification 3 as on the 5700A rear panel required when sourcing low level currents through a long cable Note Frequency uncertainty is specified to be 0 0196 of frequency setting Introduction and Specifications 1 Specifications AC Current Distortion Maximum Resistive Max Distortion amp Noise Ranges Frequency Load For Full 10 4 im BW Accuracy Q A 20Hzto45Hz E 30 pA to 220 pA 0 22 mA to 2 2 SHzto10kMz 1 For larger resistive loads Seto 10 ___ uncertainty specifications by actual load maximum full load for acc
180. oad conditions to eliminate crossover distortion Transistor Q3 provides limiting for positive output currents by absorbing further Increases in base current to Q4 once sufficient voltage is developed across the R3 R4 parallel combination to turn Q3 on Q6 provides limiting for negative currents in a similar manner by restricting the base current to Q5 Under current limit conditions dual diodes CR16 and CR17 prevent reverse base emitter breakdown of Q11and 012 respectively whilst diodes CR4 and CRS prevent current flow from Q11 and 012 to the output the forward biased collector base junctions of Q3 and Q6 respectively The overall gain of the amplifier within the specified operating bandwidth is defined by feedback network 139 R145 and R146 and is given by the expression 145 R146 R139 Stability is ensured by dominant pole compensation provided by local feedback around Q35 via capacitor C33 Additional open loop frequency response shaping 15 provided by local feedback around US U11 via R141 and C31 Fuse F1 and diodes CR14 and CR15 are included to help protect the amplifier in the event of an external high voltage source being connected to the output terminals During such an occurrence amplifier output is clamped to the 45V supply rails by CR14 2 46 Theory of Operation A8 High Voltage PCA and or CR15 providing short term protection The resulting large current flow eventually causes F1 to rupture thus providing pr
181. of repair replacement parts when product purchased in one country is submitted for repair in another country Fluke s warranty obligation is limited at Fluke s option to refund of the purchase price free of charge repair or replacement of a defective product which is returned to a Fluke authorized service center within the warranty period To obtain warranty service contact your nearest Fluke authorized service center to obtain return authorization information then send the product to that service center with a description of the difficulty postage and insurance prepaid FOB Destination Fluke assumes no risk for damage in transit Following warranty repair the product will be returned to Buyer transportation prepaid FOB Destination If Fluke determines that failure was caused by neglect misuse contamination alteration accident or abnormal condition of operation or handling including overvoltage failures caused by use outside the product s specified rating or normal wear and tear of mechanical components Fluke will provide an estimate of repair costs and obtain authorization before commencing the work Following repair the product will be returned to the Buyer transportation prepaid and the Buyer will be billed for the repair and return transportation charges FOB Shipping Point THIS WARRANTY IS BUYER S SOLE AND EXCLUSIVE REMEDY AND IS IN LIEU OF ALL OTHER WARRANTIES EXPRESS OR IMPLIED INCLUDING BUT NOT LIMITED TO ANY IMPLIED WA
182. onnects to R23 through R85 U31 will adjust the base voltage of Q14 and MP13 to make the voltage at its inputs equal Therefore the voltage across R23 will set the bias for positive output transistors In similar manner the other half of U31 will set the voltage at the emitter of MP14 equal to the voltage across R32 The voltage across R32 will set the bias for the negative output transistors With no output current the current from the positive output transistors will flow into the negative output transistors To obtain a positive output the current out of MP13 and Q14 15 increased and the current through MP14 and 015 is decreased by the same amount The total output current 15 therefore equal to two times the amount of the increase from the positive output transistors The current increment that was flowing in the negative output transistors is now diverted to the output to supply of the output and the other of the output comes from the increase in the positive output transistors Negative output currents are obtained in a similar manner When the negative output transistors current is increased the positive output is decreased by the same amount The maximum output from the amplifier for class A operation will therefore be equal to 2 times the bias current When either the positive transistors or the negative transistors current is reduced to zero the opposite side transistors will be supplying 2 times the bias current to the output
183. ontrol the scope meter The CPU communicates with the A6 Digital Synthesis PCA through serial communication lines through J1 a 20 pin cable to the A3 Motherboard PCA AII communication with the A6 Digital Synthesis PCA is through differential transceivers and transformers The differential drivers reduce noise coupling between the guarded and non guarded CPU circuits The transformers isolate the guarded and unguarded circuits The transformers are found on the A6 Digital Synthesis PCA See Sheet 7 of the A6 Digital Synthesis PCA schematic There are several miscellaneous items to note on the A9 Out Guard CPU PCA First there is a watchdog timer circuit U1 If the CPU loses communication with either the front panel or the A6 Digital Synthesis PCA the watchdog timer is not signaled which allows a hard reset to the instrument Secondly there is the calibration enable switch When 57LFC is calibrated it is recommended that the switch be set to inactivate calibrating the instrument until the normal calibration interval has expired Finally a JT AG port is available to allow programming the flash memory through the CPU when changes are made to the software This can only be used by the factory Real Time Clock Memory There is over 640 K bytes of static RAM on the CPU board The RAM has a bank of 128 k x 16 and a bank of 512 k x 16 The is also 512 k x 16 flash memory in U5 and U6 At power up the flash is moved into RAM Program execution is
184. ot used for standard uncompensated two wire ohms or ac and dc current Signal Buses The system analog and digital buses are brought to the circuit cards through the A3 Motherboard PCA connectors J105 108 and J205 208 J105 J108 provides the in guard IG digital bus signal lines while J205 208 route the in guard analog signal lines Guard is tied to chassis through a set of diodes and MOVs CR57 CR58 and and CR69 CR68 and RV 1 and prevents the guard from floating more than 20 V from chassis The guard is tied to SCOM through CR55 CR56 RV2 and R86 Note that relay K5 on Sheet 1 can connect the guard trace directly to SCOM Low Volt Buffer The low voltage buffer circuit is shown on Sheet 4 of the A3 Motherboard PCA schematic along the bottom middle of the Sheet The V3 3 input signal to U2 comes from the A6 Digital Synthesis PCA A6 U2 combined with Q1 2 7 and 8 act to buffer the V3 3 signal and isolate the output voltage from the card and Q4 limit the output current that may be drawn In guard Power Supplies The power supplies for the analog circuits also referred to as in guard supplies are shown on Sheets 2 3 and 4 of the A3 Motherboard PCA On Sheet 2 of the A3 Motherboard PCA schematic the raw transformer secondaries enter at P2 5ACI 5AC2 15ACI and 15AC2 go to Sheet 3 of the A3 Motherboard PCA schematic along with the GUARD signal RT7 10 protects the transformer from large current draws that might
185. otection in the longer term To minimize undesirable effects due to variability in fuse characteristics with operating point temperature and time F1 is connected within the overall feedback loop of the amplifier The amplifier output 1s routed to connector P108 via resistor R143 and relay K1 R143 is included to help prevent output stage instability in the presence of capacitive loads Detailed Description of the 220 V Amplifier The 220 V amplifier has a gain of 100 and provides output voltages of between 22 V and 220 V dc or ac rms at frequencies up to 100 kHz The amplifier is designed to accommodate a maximum burden of 20 mA dc or ac rms or a maximum capacitive load of 675 pF for ambient temperatures up to 40 Above this temperature the allowable load capacitance is reduced To achieve the maximum required voltage swing under ac conditions the output stage 1s operated from 375 V supply rails These rails are regulated to provide isolation from raw dc supply voltage variations caused by mains fluctuations transformer regulation and ripple To minimize output stage power dissipation particularly under dc output conditions the positive and negative PA rails can be independently switched to a value of 188 V under firmware control when compatible with the required amplifier output voltage See Table 2 15 for the supply values as a function of range Table 2 15 Supply Values as a Function of Ranges 22 V to 110 V dc 18
186. our 220v 8 is 9 OUT HI V3BUF TO VMID SNS HI TO VDIV H 5 M 1 w 9 1 er CR2 SENSE SELECT cual cans cap 1 lt SNS LO 1 K6 K6 K3 K3 10 K2 K2 7 SNS HI L 10P 10 1 4 13 FDH300A ER 14 3 k ioov 100v T 100v La CBT z 2 11 VMID IN SNS HI SNS 1 5 OSNS HI 2206 1206 1206 CR16 SOMIL Egio NC GUARD TO SCOM 1 1 9 8 SNS LO K5 9 2 1K 1K v E20 da Escher enne ec ig massa aa eee ieee forte VM VD 1W 2512 1W 2512 FDH300A RST RST CR17 IN Sus 1 DS4E A OSNS LO DS2ET 2s K10 K10 9 OUT K5 8 GF1G 13 v DS2E1 11 VDIV E30 6 NOT INSTALLED 5 2 220V TO VMID 1 2203 I our 220v 8 _ 11 1 9 VMID GUARD 1 11 1 1 GF1G i CR14 l l i GF1G OUT_LO TO A6 10 11 K9 9 A6 RET LO 13 1 11 OUT LO 1 1 1 CR56 CR57 CR58 1 GF1G GF1G 1 1 RV3 TC MEAS E12 22 I A 22 as sus 57LFC 1003 3A8 1MA IN SNS LO 2 OVER22V 2 1 of 5 E15 A Vv v 1 1 1 8 7 6 5 5 4 3 2 Figure 6 2 A3 Motherboard PCA cont Schematic Diagrams 8 7 6 5 4 3 1 P5 i cns B FAN AT MAINS END L9 R90 12VGF I 0
187. plifier in use Low Current Output Amplifier The output amplifier for the 220 and 2 2 mA ranges is composed of 032 035 Q16 019 20 and associated components This amplifier uses the 2 common for its ground reference and has its own floating power supply referenced to the 72 common The power supply is composed of transformer T1 CR26 C102 C103 U50 U51 and associated components Amplifier U49 drives a shield in transformer T1 to reduce the capacitance between 75 common and the 72 common Capacitance between the two commons appears across the current sensing shunt and degrades the frequency response and therefore the accuracy of the instrument Transistor 020 of amplifier 035 CR11 R44 R148 R47 and R198 form a pull down current source of 2 mA in the 220 uA range and 6 5 mA in the 2 2 mA range Amplifier U32 Q16 and R37 convert the input voltage at U32 pin 3 into a current that flows into R43 and forms a voltage at U35 pin 5 The other input at U35 pin 6 is derived from the resistors at the emitter of 019 R165 R147 and R48 Relay K12 switches R48 into the 2 40 Theory of Operation 7 Current circuit for the 2 2 mA range and out for the 220 range The other half of K12 switches R47 and R198 into the circuit for the 2 2 mA range and out for 220 range When the voltage at U35 pin 6 is equal to the voltage at pin 5 the amplifier is biased for operation at 6 5 mA on the 2 2 mA range and 2 mA
188. rifies that the output ac signal has a limited amount of noise in the signal A distortion analyzer is required for this test Follow the vendor s Calibration and Verification 3 Verification Tests specifications for setting up those instruments It is necessary to use a shunt resistor across the Calibrator output A set of test limits is provided in Table 3 12 See Figure 3 10 for a sample test setup Table 3 12 Harmonic Test Values for AC Current mMm Amplitude Frequency Reading Distortion mus wen o mes wes wen mms ue pea m mes wes wa mes ue en ___ wae wa emm mes wa ues o mes mes m O on mes fe 2 en wes fora ee External Trigger No external trigger mechanism is available on the Calibrator 3 21 57LFC AN Service Manual 3 22 Verification Test Check List Verification Test Procedure S Number for tne ume Test Results Verification Test Procedure Check List Pass Fail Switch set to disable calibration Red and Yellow LEDs light when load removed 0 1 O shunt resistor or during current output equivalent Output relays disconnect terminals from None instrument during self test DC Voltage Fluke 8508A or equivalent AC Voltage pone
189. rminal of 022 the drain potential of 022 is thus essentially equal to that of the 180UNR supply In this condition pin 2 of analogue switch U20 SWA is left unconnected to HVCOM and R240 is thus included in series with R241 so that the voltage at the drain of 066 is now controlled at 192 V This voltage is applied to the gate of PA output transistor Q22 resulting in a nominal regulator output voltage of 188 V For a required output voltage of zero control line ON OFF is set high This turns on 17 shorting out shorting the drain terminal of Q66 to ground and resulting in a nominal voltage of zero at this point It should be noted that and PA outputs cannot be set to zero independently as their control lines are derived from the same logic control signal Current flowing from the PA output is sensed by R88 the voltage across which is applied to the base and emitter terminals of Q23 The collector current of Q23 is sensed by the parallel combination of VR33 and R171 and the voltage developed is applied to an R C low pass filter comprising R168 and C15 The filter output is applied to the non inverting input pin 5 of one half of dual comparator U9 the inverting input pin 6 of which is normally held at approximately 3 5 V by current source CR21 and resistor R77 Under normal operation Q23 does not conduct and Pin 5 of U9 therefore remains at approximately 0 V The comparator output pin 7 therefore pulls low appro
190. rom relay K22 to SMUX line when asserted Low CKHI Connects the CHK output from relay K23 to the SMUX line when asserted Low CKIVREF Connects the IVREF voltage to the SMUX line when asserted Low INRCOM Connects the RCOM1 line to the IVREF ground reference buffer when asserted Low INIVREF Connects the ACDC and the IFBCK lines to the IVREF control amplifier when asserted Low ZIVREF Selects 0 V to the IVREF control amplifier when asserted low to select zero output current ZIVREF should only be asserted when INIVREF is de asserted ISELHNA Selects the Hundreds of nano Amp current source output when asserted Low ISELUA Selects the Micro Amp current source output when asserted Low ISELTUA Selects the Tens of Micro Amp current source output when asserted Low ISELHUA Selects the Hundreds of Micro Amp current source output when asserted Low ISELMA Selects the Milli Amp current source output when asserted Low This is the normal default ISEL line Only one of the ISEL lines is normally asserted at one time Guard Circuits 2 26 The 040 guard amplifier circuit drives ZGUARD and also HIGUARD see Motherboard PCA pins A29 and C29 whenever the instrument is put in Operate for ohms IZGRD also drives the shield to shown on Sheet 2 ofthe A5 Ohms PCA schematics Since HIGUARD is connected to the I GUARD terminal the guard amp drives that terminal plus whatever is connec
191. s for the RTCASS program will be repaired and calibrated at the Fluke Technical Support Center in Everett Washington Contact Fluke Technical Support at 1 888 993 5853 or by sending a fax to 1 425 446 6390 The address for the Fluke Technical Support Center address is Fluke Technical Support Center 1420 75th ST SW Everett WA 98203 6256 U S A Once full production is started the following service centers will also maintain and calibrate the Calibrator in Europe FLUKE NEDERLAND B V Customer Support Services Science Park Eindhoven 5108 5692 EC Son Netherlands FLUKE DEUTSCHLAND GMBH Customer Support Services Heinrich Hertz Strafe 11 D 34123 Kassel Germany and in Asia FLUKE SOUTH EAST ASIA PTE LTD Service Center 83 Clemenceau Avenue 15 15 06 Ue Square 239920 Singapore 1 1 5 57LFC AN Service Manual Specifications The 57LFC System Calibrators are verified and calibrated at the factory prior to shipment to ensure they meet the accuracy standards required for all certified calibration laboratories By calibrating to the specifications in this chapter you can maintain the high performance level throughout the life of your calibrator Specifications are valid after a warm up period of twice the time the calibrator has been turned off up to a maximum of 30 minutes For example if the calibrator has been turned off for five minutes the warm up period is ten minutes To ensure the validity of the
192. s that the NOT step was returned due to a normal termination of the calibration procedure a CAL STORE command MUST be issued to store the newly derived calibration constants into non volatile memory Once the calibration constants are saved it is a good idea to reset the instrument using a RST command For a complete list of remote commands for calibration see Chapter 3 of the 57LFC AN Operators Manual Calibration and Verification 3 Verification Tests During calibration it is a good idea to check the Calibrator fault queue after each calibration command This will alert the user to any problems during the calibration To check the fault queue send the command ERR as shown below print LFC ERR input LFC A print Verification Tests The verification tests are used as the basis of Final product testing performed in manufacturing e Automated test system design e Product acceptance by the end user This section describes the minimum testing necessary to verify with reasonable certainty that the Calibrator is totally functional and will meet its published specifications over the specified environmental conditions and for the specified calibration interval Any personnel using the verification tests must be familiar with the operation of the Calibrator and the have ability to set up and operate the recommended test equipment While the verification tests were developed for manual testing if the test steps listed are fol
193. s the 22 mA and 220 mA ranges The high current amplifier provides the 2 2 A range The output current is driven through the load connected to the OUT HI and OUT LO terminals and returned through the shunt resistors The differential shunt amp amplifies the voltage developed across the shunt resistors and generates the IFBK feedback signal to the Digital Synthesis PCA as noted above and also to U18 amplifier When IFBK andI ACDC SW signals at the input to U18 are equal the system is in balance providing the correct output current Figure 2 5 shows the operation of ac current functions Operation of the ac current function is similar to dc operation except the signal provided on the I ACDC line is ac signal generated by the DDS and scaling DACs on the Digital Synthesis The ac feedback on the IFBK line is buffered U14 and converted to DC by the averaging converter before it is applied to U9 on the A6 Digital Synthesis PCA 2 37 57LFC AN Service Manual 57LFC DC Current Low Current Amplifier 2GND Mid Current Amplifier IGND High Current Amplifier Shunt Amp Shunt Resitors IGND 2GND apv014f eps Figure 2 5 DC Current Functions 2 38 Theory of Operation Current 57LFC AC Current A6 U14 i R14 IFBK Averaging Le Converter U31 Current Scaling Error DAC 14k Scaling R3 DAC U33 TP9 U56 A7 2GND
194. se The value of each location in the wave table is the instantaneous amplitude value of the waveform for that particular phase As the phase accumulator sequences through address locations the amplitude data is routed to the 16 bit DDS DAC s U13 U44 where point by point the waveform is generated Theory of Operation A6 Digital Synthesis PCA The FPGA splits the addresses into two channels where the address of the secondary channel can be offset from the first thereby causing a phase difference between the two It also provides logic for writing the waveform data to the table The differential output current of the primary DDS DAC 013 is converted to a voltage of about 9 7 by R41 R47 U4 It is then filtered to remove glitches and clock feed thru and adjusted in amplitude by the scaling DAC U53 amp U25 This voltage can be further adjusted by adjusting the current flowing into U13 s IREFIN pin This is done by amplifying the control loop error voltage by an amount inversely proportional the scaling DAC s attenuation and applying it through R11 to the U13 pin 24 The secondary DDS channel works in a similar way AC Voltage Operation Refer to Sheet 3 of the A6 Digital Synthesis PCA schematic The output of the primary DDS channel is routed to the 3 3 V output amplifier U42 through switch U48 This amplified divided outputted and sensed the same as for V dc except instead of the sense amplifier output being applied to t
195. specifications a dc zeros calibration must be performed at least every 15 days If more than 15 days elapse without a dc zeros calibration a warning message appears This procedure does not require any external equipment or connections and takes approximately 5 minutes to complete General Specifications Factory set IEEE488 address 4 Warm up Time Twice the time since last warmed up to a maximum of 30 minutes Temperature Performance Operating 0 to 50 Calibration 15 to 37 7 Storage 40 to 75 Temperature Coefficient Temperature Coefficient for temperatures outside tcal 5 is 10 of the 1 year spec per Relative Humidity Operating sorrentina lt 95 to 43 non condensing 4096 to 50 Storage 9595 non condensing Altitude Operating 3 050 m 10 000 ft maximum Non operating 12 200 m 40 000 ft maximum Safety errr Designed to comply with IEC 61010 1 2000 1 ANSI ISA S82 01 1994 CAN CSA C22 2 No 1010 1 92 Analog Low Isolation 20V Designed to comply with 61326 1 2000 11 Class A Criteria C Line Power Line Voltage selectable 100 V 120 V 208 V and 230 V Line Frequency 47 to 63 Hz Line Voltage Variation 7 about line voltage setting Maximum
196. strap while working on this product A grounded wrist strap increase the risk of current flowing through the body Disconnect power before removing protective panels soldering or replacing components High voltage may still be present even after disconnecting power FIRST AID FOR ELECTRIC SHOCK Free the Victim From the Live Conductor Shut off high voltage at once and ground the circuit If high voltage cannot be turned off quickly ground the circuit If the circuit cannot be broken or grounded use a board dry clothing or other nonconductor to free the victim Get Help Yell for help Call an emergency number Request medical assistance Never Accept Ordinary and General Tests for Death Symptoms of electric shock may include unconsciousness failure to breathe absence of pulse pallor and stiffness and severe burns Treat the Victim If the victim is not breathing begin CPR or mouth to mouth resuscitation if you are certified Table of Contents Chapter Title 1 Introduction and Specifications IntrodUctiOD s ERR es Service Information eerte rtr e deer AGCOSSOFISS Low Thermal EMF Test 8 1 4 Rack Mount 1 4 Shielded IEEE 488 Cables 78021 Y8022 and Y8023 Contacting Fluke ede
197. t 0 5 A Relay K22 switches resistor R79 in parallel with R74 on the positive side and R78 in parallel with R77 on the negative side This parallel combination sets up the 0 5 A bias in the output stage With R79 and 78 switched out of the circuit the higher resistance and therefore higher voltage across them boost the bias in the output stage to 1 8 A for ac operation With 0 5 A bias in the output stage in the dc mode either the positive output transistor or the negative output transistor will shut off depending on the polarity of the output current at about 1 A of output current At this point the amplifier operates class B with only one or the other of the output transistors in use at a time Solid state relay U38 is used to disable the amplifier when it is not being used A high on the 2 2 DISABLE line from the digital control circuit will turn on the relay shut off the bias current in the amplifier and put it in a dormant state The transconductance of this current amplifier is 1 83 A V for ac and 55 A V for dc lt 1 A and 45 A V for dc gt l Theory of Operation 7 Current The temperatures of MP2 and MP3 are monitored with some TMP36 temperature sensors mounted to small circuit boards that are soldered to the tabs of the transistors The temperature sensors put out 10 mV degree C and have a 500 mV offset A voltage divider and capacitor on the sensor circuit board reduce 15 V supply down to around 5 V to pow
198. t coils of one of the four on board latching relays The four reset coils are also connected together via diodes 49 to CR53 so that all relays can be simultaneously reset by pulling the RLY RST line low The outputs of U14 are used to control U10 and U20 directly Outputs Q5 to Q7 are also translated by quad comparator U8 to produce the 14 V signals ON OFF ON OFF HILO V and HI LO_V This process introduces an inversion in deriving and V Outputs 00 to Q2 U17 control the output routing for the heatsink temperature monitor IC s via U19 2 51 57LFC AN Service Manual A9 Out Guard CPU PCA The CPU manages all of the internal remote functions including IEEE 488 and RS 232 remote communication calibration enable watchdog timer serial communication with the FPGA on the A6 Digital Synthesis PCA See Sheet 1 of the A9 Out Guard CPU PCA schematic The main processor U10 is a Motorola 68306 that runs on code stored in flash memory See Sheet 2 of the A9 Out Guard CPU PCA schematic The processor directs all internal operations in the Calibrator It receives commands from the IEEE 488 interface The RS 232 interface is used in the factory for special testing There are two serial ports One serial port 15 used for communication with a host PC The other port AUX can be used as a programmable serial output port When the Calibrator 1s used with Fluke s hand held scope meters the port may be used to c
199. tched to the input of U14B where it is rectified and filtered by U14A U84A and 03 before it Is switched into the negative input of the error integrator U9 09 integrates the difference between this feedback signal and the IDAC output generating an error signal This error signal is amplified by the loop compensation DAC U47 and U90 and then routed to the reference pin of the DDS waveform DAC 044 adjusting the output until the difference between the inputs of UO is zero Thermocouple Temperature Measurement Thermocouples consist of a pair of wires that are each made of different metals or alloys On one end of this pair the wires are electrically connected to each other The other end 15 terminated to copper contacts fastened to an isothermal block The voltage produced at the iso thermal block is a function of the thermocouple type and the temperature 2 35 57LFC AN Service Manual 2 36 difference between the iso thermal block and the end of the wire pair Thus to measure the temperature of a thermocouple its voltage and the temperature of the 1so thermal block must be measured Iso thermal Block Reference Junction Temperature Measurement Refer to Sheet 5 of the A6 Digital Synthesis PCA schematic The iso thermal block contains two copper buttons to connect to the thermocouple plug a precision 10 bead themistor glued between the buttons and a 6 layer PWB It is constructed to maintain as low a temperature difference
200. ted to it as well In Standby HIGUARD is not driven For volts HIGUARD is shorted to GUARD so that output terminal I GUARD is connected to and driven by V GUARD The circuitry around 040 including Q6 R58 61 VR3 C93 and K46 provide capacitive load compensation and regulate the 45 V supply from the Motherboard to about 6 V referenced to SNS HI Theory of Operation A5 Ohms PCA Compensation Circuits In addition to four wire ohms and two wire ohms the user can also select to have two wire compensated ohms where amplifiers and floating supplies are used to negate most of the effects of path loss associated with a two terminal resistance measurement instrument Sheet 2 contains the compensation circuits for the HI and LO paths HI compensation COMP OUT HI is controlled by U19 with inputs from either the internal resistance COMP RES HI and the external COMP EXT 020 provides the drive capability Similarly 017 and 041 control the low compensation output COMP OUT LO Relay K24 shorts the low compensation current inputs when not in use The maximum output compensation current exceeds 100 mA The low compensation circuit is referenced to SCOM while the high compensation circuit is referenced to FCOM The 2 Wire Comp sense either internal or remote is selected by a A3 Motherboard PCA relay The floating power supply used to power the HI compensation circuit is also shown on Sheet 2 of the A5 Ohms
201. the 57LFC 1s accomplished using two internal calibration procedures The first of these is an offset or zero calibration and requires no external standards The second procedure is used to establish range gains and other constants using external standards The first internal procedure will be referred to as zero calibration and the second will be referred to as main calibration for the remainder of this discussion See Table 3 1 for a list of the equipment required by the main calibration procedure The calibration procedures consist of a number of calibration steps While the user has no direct access to the procedures or the individual steps that comprise them an understanding of their structure makes it easy to write an external computer program to utilize them For this reason the internal procedure architecture is described in the following section Procedure Architecture There are three parts to a calibration procedure Every procedure has an entry point one or more steps and an end point In this section we will describe each of these and its implications for the programmer writing a calibration application Note In this section controller refers to the computer controlling the Calibrator The term LFC refers to the IEEE488 address of the Calibrator The examples shown are in pseudo code PROC name Defines the procedure entry point The procedure name is used to define the start of a calibration procedure There
202. the op amp Dual diodes CR31 and CR32 and associated components clamp the op amp inverting input at approximately 1 5V under overload conditions The output of U5 15 fed via R144 to voltage to current converter stage 056 The transconductance of this stage is set by R210 and emitter bias current is provided by current source 055 Diode CR47 is included to prevent reverse base emitter breakdown of Q56 which would otherwise occur under overload conditions The output from the collector of Q56 is applied to the input of common emitter amplifier Q36 this stage 1s referenced to the 45V supply rail and provides the full output voltage swing of the amplifier Collector bias current for Q26 is supplied by current source Q35 thus maximising the low frequency gain of the stage The output from Q35 is buffered by emitter followers Q11 biased by current source 08 010 and 012 biased by current source Q9 Q34 before being fed to complimentary output emitter followers Q4 and Q5 respectively The output stage bias current is defined by the quiescent voltage imposed across the series parallel combination of resistors R3 to R10 this voltage 15 the sum of the base emitter voltages of Q11 and 012 and the voltage across dual diodes CR16 and CR17 less the base emitter voltages of Q4 and Q5 and the voltage across CR3 and CR6 Resistors R3 to R10 are chosen to set this current at approximately 40mA so that the output stage operates in class A under all specified l
203. tial shunt amplifier via R3 is compared to the input signal from the A6 Digital Synthesis PCA I ACDC SW by amplifier U18 Any difference is amplified by U18 and the difference is used to drive one of the three output amplifiers depending on range to the correct output level and to correct for any distortion produced by the output amplifiers within the limits of the loop gain around the whole loop Switch U26 connects various feedback components to U18 The STBY control line from the digital control circuit turns on a switch to short U18 output to the negative input during instrument standby to keep 018 biased to 0 output The COMP3 control line switches C135 around 018 to reduce the loop bandwidth in DC mode and the LCOMP ON in the AC mode The other control lines switch resistors in and out to tailor the response of the loop as needed for each range The output U18 feeds an isolation amplifier composed of U44 U13 and associated components This isolation amplifier provides high impedance isolation from circuits referenced to 75 common to circuits referenced to both I common and 72 common The common and 2 common are separated from 5 common by the shunt resistor that is in use for each range The output of the isolation amplifier is fed to the low current mid current or high current output amplifiers via relays K10 and K1 Relays K10 and also configure the and 2 commons as required by the output am
204. to Obtain Parts Listed parts may be ordered directly from Fluke Corporation and its authorized representatives by using the part number Parts price information is available from the Fluke Corporation or its representatives To ensure prompt delivery of the correct part include the following information when you place an order Instrument model and serial number Part number and revision level of the PCA containing the part Fluke part number Description as given under the DESCRIPTION heading Quantity Refer to Contacting Fluke earlier in this manual for more information 5 3 57LFC AN Service Manual Service Centers All Calibrators delivered to the Navy contractors and subcontractors for the RTCASS program will be repaired and calibrated at the Fluke Technical Support Center in Everett Washington Contact Fluke Technical Support at 1 888 993 5853 or by sending a fax to 1 425 446 6390 The address for the Fluke Technical Support Center is Fluke Technical Support Center 1420 75th ST SW Everett WA 98203 6256 U S A Once full production is started the following service centers will also maintain and calibrate the Calibrator in Europe FLUKE NEDERLAND B V Customer Support Services Science Park Eindhoven 5108 5692 EC Son Netherlands FLUKE DEUTSCHLAND GMBH Customer Support Services Heinrich Hertz StraBe 11 D 34123 Kassel Germany and in Asia FLUKE SOUTH EAST ASIA PTE LTD Service Center 83 Clemenceau Av
205. uits monitoring circuits and diagnostic circuits See Figure 2 1 for a block diagram of the A5 Ohms PCA The last part of this section discusses diagnostic capability built into the A5 Ohms PCA See the A5 Ohms PCA schematics for circuit details Other Control and Monitor Circuits Relay Switch Thin Film Resistor Matrix and Networks Switch upply Control Compensation FCOM Circuits Active Guard HIGUARD Circuits Figure 2 2 Block Diagram of the A5 Ohms PCA A3 Motherboard PCA apv001f eps 57LFC AN Service Manual Precision Resistor Networks Fluke proprietary hermetically sealed thin film resistors Z1 5 are used in the A5 Ohms PCA While the values are not exact the thin film resistors are made to have excellent time and thermal stability with low temperature coefficients The resistors are made for 4 wire operation but may be used as 2 wire devices with degraded specifications In four wire mode the resistors are connected to OUT HI SNS HI OUT LO and SNS LO The resistors have the following nominal ohm values 0 short Z1 1 1 9 Z2 10 19 100 190 1 0 1 9 Z3 10 100 k 1 M 10 M 24 19 k 190 k 1 9 M 19 M As an example at 19 M the maximum peak current is 1 6 The limit is required because an active circuit used to guard the resistance value from leakage has a maximum range of about 33 V Exceeding that voltage
206. ummed into the filter at C76 DC Voltage Operation Refer to Sheet 3 of the A6 Digital Synthesis PCA schematic In the 3 3 V dc range the VDAC output from Z2 is applied to the non inverting input of the control loop integrator U60 The output of U60 is inverted by U87B and is buffered by the 3 3 V output amp U42 and switched to VMID by K8 VMID is switched to the instrument output by the Motherboard relay A3 K3 This output 1 sensed by NSNS switched to VDIV by A3 K2 VDIV 15 applied to the sense divider Z5 by K3 The composite sense amplifier U57 and U21 invert the sense signal which is then applied to the inverting input of U60 The net result is an instrument output dc voltage that 1s equal to VDAC The 33 V dc range operates in a similar way except the inverting amp U87B is bypassed by switch U48D and the output of U42 is amplified and inverted by the A8 High The output of the A8 High Voltage PCA 15 applied to VMID the 33 V sense input 15 selected by K2 The 330 m V dc range does not use the sense divider amplifier but instead receives its feedback through analog switch U15A U87B is bypassed in this range so there is no inversion in this mode of operation The output of U42 is then divided by 10 by Z8 with the output of Z8 connected to VMID by K7 The 330 V dc and 1000 V dc ranges are generated by rectifying a high voltage ac signal First the output of U25 a DDS generated 2kHz square wave is s
207. uracy Note Current times Load cannot exceed the maximum compliance voltage 57LFC AN Service Manual Chapter 2 Theory of Operation Introduction O 2 3 MS 2 2 A3 Motherboard tete ertet Relay Control and Switch Matrix essere 2 5 LED Control and Output Signal ere ertet Low Volt Buffer operire rer e tete oe reda deris In guard Power Supplies Outguard Power Supplies I eene Miscellaneous Circuits eere enne enne Troubleshooting Test Points ene Listof FUSES MEE AS Ohms nnne M re ERE OREG Precision Resistor Networks asas Relay Switch Matrix and Control sese Other Control Circuits Guard uuu u esee Compensation Circuits M EA Iba Digital Synthesis Precision Dual Tracking 7 V References Precision 28bit PWM Dual DC Voltage DDS Waveform Generation AC Voltage Current Operation
208. witched to the input of 042 by switch U48C This square wave is amplified stepped up rectified and filtered by the A8 High Voltage PCA to approximately the desired dc voltage This dc voltage is then connected to VDIV for connection to the instrument output and for sensing In the case of the 330 V range VDIV is connected to the sense divider amplifier by K1 In the 1000 V range U98 is used to invert the signal on VDIV This divided voltage is applied to U60 which generates an error signal This error signal is fed back to U49 Sheet 1 of the A6 Digital Synthesis PCA schematic for inversion and amplification before being applied to the multiplying reference pin of the DDS waveform generation DAC U13 The voltage at this pin controls the amplitude of the ac square wave thus adjusting the dc voltage to exactly the desired value DDS Waveform Generation 2 34 Refer to Sheets 1 and 8 of the A6 Digital Synthesis PCA schematic Direct digital synthesis was first used at Fluke in the modulation oscillator of the 6080A synthesized signal generator It uses a high speed waveform reconstruction DAC digital phase accumulator and a waveform lookup table to generate repetitive ac signals of arbitrary waveform modified and improved circuit based on the same technique is contained in the FPGA U5 The DDS circuit uses a 40 phase accumulator and uses SRAM UI to store the wave tables Each memory location the SRAM wave table corresponds to a pha
209. ximately 14 V reverse biasing CR36 and allowing the gate voltage of Q17 to be set in accordance with the ON OFF line When the PA supply output current exceeds a pre determined overload limit of approximately 90 mA Q23 rapidly starts to conduct and the filter output begins to rise If the overload condition persists for longer than approximately 75 ms the filter output voltage becomes sufficient to cause the comparator output to start to change state The positive going comparator output voltage causes Q19 to start to conduct This results in positive feedback via the inverting input thus accelerating the change in state This process terminates when the open collector output of the comparator is completely inactive In this state the gate voltage of Q17 is pulled up to approximately 7 5 V by R159 and 019 15 saturated 017 is thus turned shorting out the drain of Q66 and resulting in the PA output being reduced to zero Reducing to zero causes the output current to fall and consequently Q23 stops conducting The filter output voltage applied to the non inverting pin 5 comparator input therefore starts to fall When it reaches the level on the inverting input the collector saturation voltage of Q19 the comparator reverts to its original state Q17 is again allowed to be turned off by the low 14 V line and the voltage at the drain of Q66 begins to increase slowly towards its normal reference value as capacitor C13

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