POLAR INSTRUMENTS Toneohm 950 Service
Contents
1. C D E C706 U25 47n xp DMM HI PLANEVs FF 4 1 yo R158 Y INH 10 7 di U26 45A 14 8 LO gt R161 R289 4052 lt 1 0 A290 5D0 40 sy H O 100K Cope a UNE BUSY ay T 088 mes ER 9 m au 35 11 0 71 4 2 COMMON E u65 R159 35 77 REF257 50 m 036 2 gt 29 BEF our BS Y 201 131 2008 1 224 47u R162 28 y R160 15 T yg vic H R165 i 20K SEND B3 Y BEF RUN L_ gt 8 H N HOLD B2 U28 52. I RVI dM 777 007707077707 E Fitted from S No 012213 I 45A U3F R717 251 ee D SAMPLE 10M R716 10K 74HC04 PHASE gt C703 n252 4n7 C74 Hh 10M U12 ur R714 3 1 1855 4 cl our LA ATREA BA 10 196 100 DEDE wep ES 84 GUARD 10K 5 Y NE 7 lt IPLANE 9 C64 L 59 2 w CLAMP 45A 7 X HN D25 D24 iub UU 4 TLC279 100K 196 MO DIODE WF DIODE 8 RET ve Hd JP12 U6A R58 U7B Re36 1K x3 HL cao T 2 R292 100K 1 _ 6 gt Y VH
3. B C D E 45D 45A U21A iene D races 4 45A 09 al 5A 1K PNP CLK U23C Rs 2 4016 R134 R147 4013 516 22K mias p Rid 10K R207 4 C29 1K8 Pus T 10K U5B 10uF LF353 270 14148 2 A 21B Pin7 to 5A 6 PNP T a Y R151 R279 R135 E Invert ON for uV 1 4 10 gt T 2 024 157 22K e R278 2 14 1 R145 LM339 12 Vv R136 2140 HS OtUF M E O Ls v lt gt R149 Pin7 to 5A 777 R137 D cm lt 47 d 5 2 R150 VOLUME POT2 INH 7 47K R280 1 4 10 8 R133 360K Tone Gen C gt aen 4 22K U64 6707 10 5 153 0 1uF Dak 5A 470 092 177 U208 R208 8 7 0170 10K CA3080 1 Hi 60mV 10 P R281 pl 8 5 13 1 10 L
4. 950 T U50 Sensitivity 5D R191A BDO 2 B174 D53 OHMS 100K Ganged 801 419 8 San HI75 4 Z0mOHMS DS 2 VOLUME POT1 BD 7101 Rize 2708 2012 13103 0317 RS TIL NN Ee 5 12 14 xum RIS 1 BDS i 507 18 88 36 19 ae Riso TRACE QUADRANT O R700 330R DS 2 ii VOLUME PO 5D U51 P E E 2 R182 77 BEVERSED BD O 7 BD O 7 Ho go 5153 20mv 208 7101 94 Riad 50V don 8188 esta xx Riss 2708 BEANE py i 12 04 04 12 R186 390R 22 187 3908 BH NPY 068 nipe Q RIR PROBE 3 HEADER20X2 OST as 18108 06 19 22 Riso 3 lt La iT DMM_LO ur Tour 330R Hd oc HI z LK 74HC374 Rum 0 R283 390R 42 5 Bt 87 UNSAL
5. I RVI dM 777 007707077707 E Fitted from S No 012213 I 45A U3F R717 251 ee D SAMPLE 10M R716 10K 74HC04 PHASE gt C703 n252 4n7 C74 Hh 10M U12 ur R714 3 1 1855 4 cl our LA ATREA BA 10 196 100 DEDE wep ES 84 GUARD 10K 5 Y NE 7 lt IPLANE 9 C64 L 59 2 w CLAMP 45A 7 X HN D25 D24 iub UU 4 TLC279 100K 196 MO DIODE WF DIODE 8 RET ve Hd JP12 U6A R58 U7B Re36 1K x3 HL cao T 2 R292 100K 1 _ 6 gt Y VH 0 01 CB CLK 177 I D96 4 Hi CLKOUT 1 5 2 13 T lt vsHoRnT L 7650 3 en 114148 rh R237 1K 4052 R57 5A B R68 TLC279 PHASE gt Sensitivity Pot 10K 19 5s 100K 1 R60 10K 196 R294 C704 R291 4 7 100 196 1M 1 407 Ui lar 91K 1N4148 C18 C17 SZ FF u
6. B 412V 080 4 45V DSO i 104 2N3906 Al R92 ako 1K To front panel connector 5V DS 4 R90 R123 R102 eii Ut6 un R105 LM339 A 2 DS 2 1 TR al 22007 R112 BOK 1 PIN OF POT TO OV DS 8 E K 07 Roe l ud DC 022 4 10K 1K 1N4148 oV DS a 140 ai ps R108 5D R122 45V DS 1N4148 R107 390R 390R o 33pF WF 144007 ov DS R101 T 1s AME 4 Y 1 R286 7 R124 R97 D40 K6 U19D A ua oV DS R103 1 0 45V DSO 1074 gt 10 ILQ74 220K 19 ov DS R93 FN 1N4148 2R2 bee ov DS ov DS NO TRACK DS 45V DS 100K e 100K 10111 R265 10K 5D 9 R98 t 5 55 SAikast REEN B Q12 Lt R709 180K 196 C C74 9 R89 E m Hall lt Optional R74 gt R270 10K 4 R263 100R Al 470K A 222 2 1 R271 1N5401 U13C 2 2 Res ld U60A gt 0618 2 1 R264 100K LF353 1 10K LM339 car R99 C72 R267 47K 1 0 oV DS 5A Fast D 030 o 1 032 MBR745 RA x 1 708 1N5401 77
7. 12V 50 45V DSO k 04 R104 2N3906 t R92 1K To front panel connector 5V DS 3K9 d UISA R123 R95 R102 RR lt 108 men R105 A Maso SK 1 PIN 3 OF POT OV DS 1 4 C22 DS POT2 R100 K Q3 3K9 R106 2 4 9 R91 m ovbs nA 7 140 Tr 021 D38 21077 45D 8368 5V DS 039 mane 390R sach 1 4007 lt 106 4 220K 1 ov bs ES DS 82 R97 EA R286 777 R124 SX 1K0 AR 10K ILQ74 i ov DS R103 5V 050 7 ILQ74 a Fd ov DS R93 4 1N4148 2R2 1 VDS ov D R94 100K 1 ov DS 0 TRACK DS R98 R89 180K 1 10K 5V DS U13C s R88 1 10K LM339 020 5 wp 100 1 Polar Intruments Ltd Byler Garenne Park St Sampsons Guernsey Channel Islands Inst i 950 Drive Source B C D E PLANE J2 JP8 ji 00000 Headphones 1701 10uH 4 VPLANE R710 di t 82232 VSHORT C709 0710 4 470pF 470pF Track DS Current Probe Jp 1 J3 2 9 4 d 7 9 3 10 10 PROBES 1 Kelvin 4 70 2 82 Polar Intruments Ltd _ m Garenne Park St Samp
8. 5UREG USES 4053 ON TONE 9 GENERATOR IAGRAM T D15 D16 T T R46 R272 R273 R45 2 1 sone 48 1M 196 1R 20 lt lt C80 22U S 92 018 50 R713 05 Boards Not 10K and later used R30 a 018 cei 1N4007 T on970 10K Sev Ohms Adjust 400V 100 R31 014 R32 Y 8K2 R712 8K2 47 x 2 0628 R287 8 S 1 27 A 200R ae og R276 R277 1K 1R R274 4 LONI 20 SNE RELAY Kelvin Connected D88 94 may be omitted when D relays are used 04 1228 AS C NULL D8 D89 D9 D9 D93 D9 R27 68K 1 H vo p Yi 7 5 R26 470K R1 R2 R3 R4 R5 R6 8 U3D 3120 To GEN R29 10K OHMS 2 9 8 INH dh 74 04 1 8 K7 pl P K10 pK P 12 B 1200 THRESHOLD E 5 1 A RELAY SPST RELAY SPST RELAY SPST RELAY SPST RELAY SPST RELAY SPST RELAY SPST H2 EE 52 R38 R39 R40 R41 R42 7 1 0 1 2 i ifi NC HR ul 10R 1 56R 1 5K6 1 1 11 196 2 1 All Diodes 1N4148 unless specified 4 6 SOURCE n I Polar Intruments Ltd R284 Garenne Park St Sampsons Next Next 1 Guernsey Channel Islands to MEDIUM to Inst i dini High ud LOW 4 970 Current Source
9. lt gt mw R295 1 10K 196 R2 A dn des ET gt E R52 gt TLC279 10K 196 a 47u 45D ap R53 R51 A 9 2 1 t E TLC279 10K 1 10K 1 p 45A lt gt 47 I 0 R64 10K Hime a 1K TLC279 R83 R86 10K AP 8 IPLANEV 2 eu R85 47 100K 5A 56454 50 45A o PLANE U18D 5 330R in later units I bo 25 48 R82 ARROW OFF 5 R78 U17B 4 7 13 1 100K Y LM339 U3B 74HC00 later units 74HC132 T 1 3 4 1 1 12 0410 45D R80 4 7 CENTRE 5 R79 74HC04 13 sa pur 45D 74 08 74HC08 010 R75 PER NW a u R63 8 10K R247 13 1 7 7 100k LI 7 9 gt 10 3 1 16 e gt 10 47 TL0279 C15 LM311 4 7 74 08 Sr S Y R248 5K6 470K Polar Intruments Ltd Dosen Garenne Park St Sampsons Guernsey Channel Islands Inst i 950 Tte Plane Input Amplifier A B C D E
10. 201 17 X 4 3mmSpacer 9 O MQX138 1 X 28 PinIC Socket 238 2 LCD Connector 100K 1 4W 1MO 1 AW 200R 1 4W 22K 1 4W RCF270R 270R 1 4W RCF330R 4 3308 1 4W pcd 390R 1 4W 5 5 5 5 5 R197 R174 R175 R176 R177 R178 R179 R180 R181 R182 R183 R184 R216 R217 R218 R219 R220 221 R222 R223 R224 R700 R701 R702 R703 R186 R187 R188 R189 R190 R214 R215 RCF39R am 1 4W 5 R227 R228 R229 R230 R231 R234 R233 RVB320 1K Preset R196 RVP114 100K Panel Pot R192 RVP115 100K Panel Pot Dual IR gt O O SWB141 Push Button 53 54 55 56 57 58 59 510 512 513 514 98 1 Cabe WMAT99 1 WP BoardCable 206 1 Drive SourceCable 8 2 REPLACEMENT PARTS MAIN BOARD KIT CEA103 12 10uF Electrolytic C4 C5 C29 C41 C49 C50 C52 C53 C71 75 C78 C82 CEA105 220uF Electrolytic C32 AA E A CEA117 2 200 Electrolytic C40 C43 C45 C46 CEA122 iuF 63V Electrolytic C75 C79 CVD101 24 0 Polyester C1 C6 C7 C8 C9 C14 C15 C17 C18 C26 C31 C33 C56 C64 C65 C70 C72 C74 C75 C76 C78 C79 C85 C90 C39 C73 C77 C89 C705 C706 CVD105 3 0224F Polyester C36 C80 C81 2 82pF C19 C88 CVD109 0 1uF Radial Ceramic 48 83
11. EH HD4 04148 Spee 1 808 112183 05156 DEC 2 BD 0 7 45D0 pr 078 za 3308 5D RP5 VSS GND VDD VCC 50 CS7 11492 8 22 052 ue 74HC374 051 050 052 046 047 048 BDO 2 po 3 SHON y 801518 I x N N Y bown 6462 027 4 UP X RIGHT DOWNS BHO oe BD 390R pHa 55 2 REVERSED eb gel Q6 06 390R 18 18 4 R216 R218 R219 07 07 NO TRACK DS 270R 270R 270R oc PA G 50 U57A 74HC373 9 Y CS8 R703 ARROW OFF ide YS 330R 74HC139 R220 R222 R223 270R 270R 270R S2 1 54 S6 S8 810 812 813 514 20K 2 Ohms Super Shorts 2A 20mV 20mV 20V Plane CENTRE R224 S3 Ohm Late S5 S7 S9 2K Early 200mOHM 200mA Trace a a Polar Intruments Ltd Garenne Park St Sampsons Guernsey Channel Islands Inst Title Front Panel page 1 E B
12. DC voltage source variable from 1V to 10V and accurate to 0 1 High tolerance resistors 0 5 of the following values 10 1 serial numbers below 005975 only 2002 1000 10 and 0 10 Switch on and allow the 950 to warm up for 15 minutes Plug in the Needle Probes and press 20V Apply 10V DC to the probes and check that the reading is 10V 4 Connect a 1KO 0 596 and a 10 0 5 resistor in series Apply 10V to the series resistors This produces 10mV across the 1 Resistor Press 20mV and check that the reading across the 10 resistor is 10mV 4 Adjust the voltage source from 0 to 20V and check that the tone varies in pitch A steady warble should be generated with a negative voltage Apply 1V to the two resistors and press 2mV Check that the reading across the 10 resistor is 1mV 4 Check that varying the voltage generates varying tones No tone should be produced below about 50uV Press 20KO and measure a 10 0 5 resistor The reading should be within 496 A warble may be generated in this range a Serial numbers below 005975 Press 2KQ and measure a 1KQ 0 1 resistor The reading should be within 4 b Serial numbers 005975 up Press 2000 and measure a 1000 0 1 resistor The reading should be within 4 Press 2 and measure a 10 0 196 resistor The reading should be within 496 Apply solder to the wire ends of a 100m4 0 5 resistor Press 200mO and measure the resistor by pressing the probe ti
13. 77 33pF 33pF 477 4MHz Ceramic res 1 Polar Intruments Ltd Dolor Garenne Park St Sampsons Guernsey Channel Islands Inst so Te Microprocessor A B C D E B C D E 5 09 1N4148 010 1N4148 4 lt 56R C4 011 1N4148 DS Uu Dia JP13 a Vi 1N4148 2 Ri 7 E 8 1K 01uF Y pi F i U2A y u R17 2 C90 U2D JP11 1 3 12 020 3 al 1 14 10 R22 10 R16 100K 1084 AUF i3 mm Trace 8 1K TL084 3 20K 1 R20 05 297 C6 R23 lt 7 5 45AO 10uF 100K uf 1 0 A
14. Power cord color codes are as follows Europe brown live blue neutral green yellow earth ground United States black live white neutral green ground POWER SUPPLY Check that the indicated line voltage setting corresponds with the local mains power supply See the rear panel for line voltage settings Instruments with a serial number prefixed with a letter e g A1234 are configured for 90 110 Volts only Changing the line voltage settings on this instrument must only be performed by a skilled electronics technician Instructions for changing the line voltage settings are contained in Section 5 vi OPERATION This manual contains instructions and warnings which must be observed by the user to ensure safe operation Operating this instrument in ways other than detailed in this manual may impair the protection provided by the instrument and may result in the instrument becoming unsafe these instructions for later use The unit is designed for use indoors in an electrical workshop environment at a stable work station comprising a bench or similar work surface Use only the accessories e g test probes and clips provided by Polar Instruments The instrument must be maintained and repaired by a skilled electronics technician in accordance with the manufacturer s instructions If it is likely that the protection has been impaired the instrument must be made inoperative secured against unintended opera
15. gt DS 2 VOLUME POT1 6 B176 2708 9 177 12708 SKO Volume 12 R178 L270R 272 20 HMS R192 15 100 18 184 em QUADRANT O 9 R700 R DS POT 9 Css 330 VOLUME PO d 45 d REVERSED E BDJ O 7 BDJ O 7 H 500 5A 5D Fe R185 2708 PLANE 7 12 R86 3808 2 STANDBY 15 x R187 390R ROBE 1 u C68 C69 16 RT88 3008 22 PHOBE 2 HEADERAUXE C66 eS At C57 our AX AUF R701 ES pou we lt DMM LO C67 10uF 10uF AUF CS6 330R lt HI TES BDIO BDIO 4 13 12 DEC 1 13 18 BD O0 7 45D 18 19 3308 50 RP5 VSS GND VDD voc D 87 c 8 22K 5 777 Ugo U49 74HC374 D50 052 046 047 048 Q0 Do y y E 55819 RIGHTY LEFT Y DOWNY BDP 85 R215 1 1 1594 Dana NO TRACK DS BD6 ED 18 27 09 18 390R R216 R217 Ret8 R219 270R 270R 270R 270R oc PH G 50 R703 ARROW OFF idie 330R 74 139 R220 R221 R222 R223 270R 270R 270R 270R 1 1 52 84 86 R224 200R 2 Ohms Super Shorts CENTRE Q10 00 270R NPN S3 85 87 89 208 200mOHM TRACE PLANE E Polar Intruments Ltd Dolo Garenne Park St Sampsons Guernsey Channel Islands Inst Title 970 FRONT PANEL PAGE1
16. 0 01 CB CLK 177 I D96 4 Hi CLKOUT 1 5 2 13 T lt vsHoRnT L 7650 3 en 114148 rh R237 1K 4052 R57 5A B R68 TLC279 PHASE gt Sensitivity Pot 10K 19 5s 100K 1 R60 10K 196 R294 C704 R291 4 7 100 196 1M 1 407 Ui lar 91K 1N4148 C18 C17 SZ FF u lt gt mw R295 1 10K 196 R2 A dn des ET gt E R52 gt TLC279 10K 196 a 47u 45D ap R53 R51 A 9 2 1 t E TLC279 10K 1 10K 1 p 45A lt gt 47 I 0 R64 10K Hime a 1K TLC279 R83 R86 10K AP 8 IPLANEV 2 eu R85 47 100K 5A 56454 50 45A o PLANE U18D 5 330R in later units I bo 25 48 R82 ARROW OFF 5 R78 U17B 4 7 13 1 100K Y LM339 U3B 74HC00 later units 74HC132 T 1 3 4 1 1 12 0410 45D R80 4 7 CENTRE 5 R79 74HC04 13 sa pur 45D 74 08 74HC08 010 R75 PER NW a u R63 8 10K R247 13 1 7 7 100k LI 7 9 gt 10 3 1 16 e gt 10 47 TL0279 C15 LM311 4 7 74 08 Sr S Y R248 5K6 470K Polar Intruments Ltd Dosen Garenne Park St Sampsons Guernsey Channel Islands Inst i 950 Tte Plane Input Amplifier A B C D E
17. 86 702 707 714 CvD113 3 JF Polyester 023 034 088 C2 DSP101 40 Diode Signal 150mA 04 D5 06 D7 D8 09 D93 094 096 097 DSP107 6 Diode 1N5401 D31 D32 D35 D73 D77 D78 8 3 TONEOHM 950 SERVICE MANUAL cares 1 eae E CI E 6 174054 U28 U39 U40 U46 U47 063 1 234 1 Quad Opto Isolator U19 123 2 6 8 1 MQX139 2 40PINICSKT 237 4 635mmSpadeConnector MQX300 5 immSocket RCCi61 2 V33ZA5 1 RCF100K 20 100K 5 R6 R7 R17 R33 R72 R78 R83 R93 R128 R130 R138 R152 R154 R158 R164 R247 R259 R264 R289 R297 RCF100R 2 1008 596 R79 R298 8 4 5 RCF10K 596 R12 R29 R31 R63 R64 R74 R75 R86 R88 R89 R112 R124 R127 R147 R155 R171 R207 R208 R209 R256 R260 R265 R279 R281 R282 717 FRGFTSOK OR 271 PRCFISK 1 15K 5 ROBT RCF1KO0 25 1KO Ex R15 R16 R18 R21 R23 R92 R100 R109 R129 R201 R206 R213 R234 R235 R236 R237 R253 R258 R263 R266 R269 R272 R276 R286 R290 Berke 2 pik S 6 20 5 5 R22 R28 R162 R240 R241 246 RCF22K 22 5 R133 R134 R136 R137 R157 R165 RCF470K 470K 2 R26 R80 R153 R156 R249 R262 R270 R1
18. As defined by Installation Category II Overvoltage Category 11 in IEC664 Pollution Degree 2 IEC664 Power Requirements 230 10 115V 10 or 100V 10 at 50 60Hz 25VA Fuses Below Serial N 11244 One fuse 230V 160mAT 115V 315mAT Serial N 11265 12212 Two fuses as above Serial N 12213 up 230V 125mAT 115V 250mAT Physical characteristics excluding accessories Dimensions 305mm 12 in wide 150mm 5 9 in high 275mm 10 8 in deep Weight 3 5 kg Flammability Enclosure to UL94 0 TONEOHM 950 SERVICE MANUAL SYMBOLS AN REFER TO MANUAL These sockets are for connecting only Polar Instruments probes and connectors for use as described in the Operator Manual To prevent damage to this product and to ensure its safe use observe the specifications given in this manual when connecting to terminals marked with this symbol ACCESSORIES Standard Accessories Needle Probes 950 Plane Probe Clip assembly 950 Current Trace Probe assembly 950 Stimulus Lead Set of 4 Lightweight Headphones Optional Accessories Bare board Stimulus Lead set 0 025 Bare board Stimulus Lead set 0 031 Bare board Stimulus Lead set 0 040 Bare board Lead set universal Service Manual ACC152 ACC113 ACC114 ACC134 EPM115 ACC121 XG25 ACC121 XG31 ACC121 XG40 ACC154 MAN130 5 CONTENTS Xi TONEOHM 950 SERVICE MANUAL Xii SECTION 1 PERFORMANCE CHECK MAINTENANCE AND
19. CALIBRATION OF INSTRUMENTS For most of Polar Instruments products there are two maintenance procedures the Performance Check and the Calibration Some instruments may have a single combined procedure Performance Check The Performance Check or Checkout Procedure is used to verify the basic functions of the instrument This does not usually require the removal of instrument covers but may require the use of external test equipment This procedure is not intended to verify the calibration of the instrument Adjustment Procedure The Adjustment Procedure or Calibration Procedure is used to check and if necessary adjust the instrument s calibration settings Before carrying out the Adjustment Procedure the instrument s Performance Check if applicable should be carried out and any detected defects should be rectified The Adjustment Procedure and rectification of defects should only be carried out by qualified technician Recommendations for Routine Maintenance Where a Performance Check is available for an instrument this may be used as required to confirm the basic operation of the product To maintain the calibration of an instrument it is recommended that its Calibration Adjustment Procedure is carried out at intervals not exceeding 12 months 1 1 TONEOHM 950 SERVICE MANUAL PERFORMANCE CHECK Equipment required Procedure 1 2 Sn 10 11 12 13 14 15 16 17 18 19
20. D E 4 R227 R228 R229 R230 R232 R233 39R 39R 39R 39R 39R 39R 054 S Y K D76 NC y y EY Ne BACKLIGHT ARRAY 21 201 1 23 T C58 22uF 54 17 2 99 32 4 4 25 de 10103 8226 47K Ca Dez Bee E i 1219 2 C59 22uF G2 28 DMM LO 4 27 10 DPT 16 25 o gt 28 9 121 pr 061 1 6700 89 8 18 51 23 30 7 19161 2 R194 2n2 3i 6 20 8 poi DMM Hl gt H 1 0 _ 6701 27 34 d 202 R196 C 1 38 NITET 1K af 45A LCD 39 40 RISE Volts Cal 22K C60 5 100pF R200 wo US5A 5 DP1 4070 1 550 5 7 gt U56 R199 4070 ax xo H3 1 0 2 15 U55B He 4 2 x7 2 4070 0 11 10 R198 1 0 4051 USEC 2 La DP ES DEC 2 4070 2 NOTE Pin 7 to Test PIN 8 TO GND 1 VE SUPPLY FOR 4070 4051 BE Polar Intruments Ltd Garenne Park St Sampsons Guernsey Channel Islands Front Panel page 2 E
21. and return to standby Disconnect the Plane Probe and Clip from the 0 10 resistor Turn DRIVE SOURCE to maximum Select 20mV connect the Needle Probes and drive source leads across the 0 10 Resistor and note reading Select 200mA Check that reading is 10x Reading noted above 10 Turn DRIVE SOURCE to minimum Check for 0 1 Disconnect all cables 1 3 SECTION 2 ADJUSTMENT PROCEDURE ADJUSTMENT PROCEDURE WARNING Hazardous voltages are exposed on the PCB when the cover is removed This procedure should only be performed by a technically qualified person aware of the hazards and taking all reasonable care Equipment required e High tolerance 0 1 voltage source 10V and 10mv e High tolerance 0 196 10 and 100 resistors DVM Power Supply Before connecting to the supply 1 CHECK THE MAINS FUSES see SPECIFICATIONS 2 Connect the 950 to the appropriate line voltage and turn on 3 CHECK the front panel lights sequence and that the 950 stops in the 20V range PUSH 20mV Display Calibration 1 Connect the Needle Probes to the 10mV source 2 Adjust POT R196 top RHS of Front Panel board for a display of 10 00mV A2D Calibration 1 Turn the power off then hold down 2mV and PLANE re apply power 2 Connect needle probes to 10mV source 3 Observe the Active and Standby Pass and Fail LEDs while adjusting R163 the tone will decrease as the calibrated position is approached Whe
22. for vectored plane stimulus Controls hardware and performs current calculation Keyboard and display D2A 3 1 TONEOHM 950 SERVICE MANUAL Main Operating modes Track resistance Current is injected into the track with the needle probes using the CURRENT SOURCE module the nV AMPLIFIER conditions the resulting track voltage and displays the result directly on the LCD Track Current 200 2A These ranges compute the current by measuring the voltage drop across a length of track carrying the fault current and then injecting a known current in addition to the fault current The voltage drop is then re measured and the resistance calculated hence the fault current can be derived e g Track Resistance V due to fault V due to fault V due to injected Injected V due to fault Hence Fault Current Track Resistance The 950 first reads the track voltage with the uV AMPLIFIER and uses the A2D2A to the value The amplifier auto ranges if necessary then a small current is injected from the CURRENT source the track voltage is read again if the second voltage is not significantly different 1096 higher the 950 injects more current This process reiterates up to a maximum of 240mA injection at which point the microprocessor will force a calculation and send the resultant value to the D2A This is sent both to the front panel meter and via the conditioning network on U59 Schematic 1 to the TONE GENERA
23. relays are used t P U4 R28 20K TO uV AMP xo x 1 JOHMS_NULL D8 D89 D9 D9 D9 D9 09 MEE Er R27 68K vo 1 1 7 4 5 R26 470K R1 R2 R3 R4 R5 R6 R7 1 USD 31 To TONE_GEN R29 10K OHMS 9 INH 1014 7 74 04 916 P K7 gt P K9 gt K10 Pi K11 K12 2053 lt 200m0HM_THRESHOLD RELAY SPST RELAY SPST RELAY SPST RELAY SPST RELAY SPST RELAY SPST RELAY SPST R2 E HJ xz R3 R43 R37 R38 n p 180 1 1 All Diodes 1N4148 unl ifi ie 11R 10R 1 56R 1 5 6 1 560K 1 11 1 iodes 8 unless specified 5 4 4 R284 1L SOURCE 1RO 196 SUPA 200m 2R 200 OHMS 20K 1 100mA 10mA 50mA 200mA Polar Intruments Ltd Byler Garenne Park St Sampsons uim Guernsey Channel Islands Inst i Current Source A B D
24. select the voltage via U24 on the Tone Generator schematic or gate the supply via Q2 and U62B Q2 and D13 also afford protection against inadvertently connecting high voltages to the probes The voltage is applied via relays R1 to R7 across a series resistance and via the Kelvin connected Needle Probes to provide a known current through the track resistance under test In order to correct for offsets caused in the needle probes when measuring low resistances U4 and associated components apply offset to the uV Amplifier in order to achieve a zero reading in 20 and 200mQ in the range offset is applied to give a stable reading but a zero is not achieved when the probes are shorted Plane Amplifier and Vector Discriminator Refer to Plane Input Amplifier Schematic The Vectored Plane Stimulus sets up a field on the plane under test such that when the plane is probed the following waveforms are detected above the short two positive going half sine waves below the short two negative going half sine waves left of the short a positive followed by a negative half sine wave right of the short a negative followed by a positive half sine wave The magnitude of the half waves detected increases with increasing distance from the short 3 3 TONEOHM 950 SERVICE MANUAL The 950 extracts this information as follows U12 Amplifies the low level signal from the Plane Probe this chopper stabilised amplifier is clocked by a signal synchronous with
25. setting NOTE 100V instruments cannot be changed SECTION 6 FAULT DIAGNOSIS WARNING Service of this instrument should only be performed by skilled electronics service personnel Hazardous voltages are exposed on the PCB when the cover is removed These procedures should only be performed by a technically qualified person aware of the hazards and taking all reasonable care TROUBLESHOOTING HINTS 1 If the instrument is completely dead check the fuses and line voltage selection Inspect carefully for signs of damage loose wires etc Hectify any faults before applying power If there is no beep or flashing LED sequence at switch on the microprocessor is not operating Check the internal power supplies ROM crystal and microprocessor reset circuits If there is an OHMS fault check the input amplifier in VOLTS mode first then check the operation of the current generator If ACTIVE cannot be engaged in PLANE SHORTS check the 5A fuses in the stimulus circuit The connections to the plane drive sockets should also be checked and the sense coils which should be close around the sensor IC In TRACE mode for optimum sensitivity tune the circuit to the Trace Probe Probes may differ 6 1 SECTION 7 MAINTENANCE AND CLEANING Cleaning Clean the unit with a cloth lightly moistened with water with a small amount of mild detergent Alternatively a cloth lightly moistened with alcohol ethanol or methylated spirit or isop
26. the Vectored Stimulus to minimise clock noise on the a c output signal JP12 connects to the Drive Source Sensitivity control to allow user adjustment of sensitivity U6 forms an active rectifier for the incoming signal which is taken to sample and hold gate U8 along with the unrectified component U8 is clocked and gated so that the peak amplitudes of each halfwave in both rectified and unrectified form are sampled and held on C11 C12 C13 and C16 Magnitude signals on C11 and C12 are added then switched via U25 A D Converter schematic and U59 Microvolt Amplifier schematic to the LCD and TONE GENERATOR respectively C13 and C16 hold the unrectified component of the plane signal here only their polarities are of interest these are detected and converted to TTL levels by comparators U10 and U14 the two resultant signals QUADRANTO and QUADRANT1 are taken to the front panel and decoded to illuminate the appropriate direction arrow Finally U17A and B monitor the level of PLANEV and through the control signals ARROW OFF and CENTRE 1 Turn the arrows off when the probes are open circuit 2 Allow the QUADRANT signals to control the arrow when the plane is being probed 3 Turn all the arrows on when the probe is a few centimetres from the short Vectored Plane Stimulus Refer to Drive Source schematic The stimulus runs at power line frequency and provides a nominal 2A peak current from top left to bottom right of the plane during th
27. 1 L 1K 22R R269 1K 22ZA2 1 185 S n 073 R125 12 PLANE DS 5 2R 1N5401 2R Optional R261 i P YELLOW STANDBY J Not Fitted 1R5 S n13884up 011 C77 101 R262 C174 Hall u 47K 470 078 R707 1N4148 AUF D31 R260 use U61D 1N5401 R201 177 14 A dde D34 10K F4 1K 1N5401 MBR745 Y R258 IK ep Bros C78 9 HI o A C LM339 LM339 os DO LF353 1008 BLU E 4 1N5401 R259 100K 76 060 T or 7 2A gt EM 22ZA2 R109 R128 5A lt 777 2APHASE Ba gt 1K 100K R130 R132 C26 as 1588 R111 0158 al ur Ph 5 0150 C27 ou K R129 a FL Uzoc 2 U15C Am jd 1084 14 13 4 7 74 00 C28 01 74HC00 lt LM339 Co4 Ulu 1 4 5 Haar R131 5 U18A Optional 548 1 47K 1 2 PHASE NU 74HC00 later units 74HC132 Polar Intruments Ltd Garenne Park St Sampsons Guernsey Channel Islands st 950 Tile Drive Source A B C D E
28. 14 Y A2D Calibrate 1 BUFOSCOUT _ B 2 0 1 x 4800 83 OSC SEL test HZ Dr p B comp o sa 3 R164 23 08G OUT LBEN H8 4401 Gi 84 B2 038 OSC IN HBEN 02 62 8 24 B3 R288 1 0 20 8 8 B 82p 100k CE LOAD So 8484 REF 1K 7109 02 1304 04 15 10183 OUT TT U42F 18157 0713 124 B8 IOUT 4 HIGH 4 12 0800 3 A2D2A 0290 en 113 clk 2 A2D2A 74HC374 45A 74HC32 IWR 4 032 74 32 D 0 Line Fuses a 2 Ve 90 120 250 IEC filter LK7 LINK Only Fit Lk7 or Lk8 220 240V 125mA T JE 045 L 2 9 2 Zt 2 00uF 047 C49 R168 x in at N 045 LINK Ar tour 710 E T T Y Y T E tuF 2 33235 wo2 2 41 086 7 2200uF lt 048 50 2 F5 2 R169 1M0 neum 031 15D duF TE 10uF 87 Not Fitte LM7805 9 a C51 400V T 1 i RELAY 5 I 177 C40 170 LK 2200uF Ca _ ce 033 5D voc VDD V VEE 5A V 51 10uF F duF 10R LM7905 9 1 O 2 142A C82 T 230 3 3 77 777 12408 jour C e No 3 VSS POWER 115 3 F7 0 5AT R167 D43 pm i um O gt wog VI 2 230 Transformer C86 1 C43 gt C44 o d 2200uF AUF 115 id 1 1 Line Select 711 33ZA5 ala Polar Intruments Ltd Baler Garenne Park St Sampsons Guernsey Channel Islands Inst Title 950 A to D Conver
29. 23 24 R171 55 110 83 10 D D 45D REVERSED gt G29 30 A 0 15 91 5DO EN 1 14 12 1 x 2133 526 RP 937 38 R173 gt 74HC138 hus BAO 499 390R C52 r TJA2D2A 10uF U42D U18B BD 0 7 2 DMM_HIL 1 4 4 777 MREQ 74C04 bt Lo gt 7 RST 1 74 00 Ea 1 2 RIN VR 74HC08 6 U29C U63 7705 DIR Hs T C56 Sr 9 11 DO Qo VOLTS Aste s B8 cmo lm ud 8 i nes B MH MES T otur 100 777 03 0315 110 2185 00 45 04 04 2 1000 2164 A4 5 90 B4 05 Q5 He OHMS 18783 4 9 HS NO PLANE DS C gt 06 Q6 H CONTACT 1 8182 2 TN B2 18 509 3 07 Q7 HIGH Bi Al 81 E doc 74HC245 DIO 74 245 10uF 2 9 HH 8 vB 74HC374 BDB 0 7 Dio lt gt D 0 7 RP6 8 22K 1 20 3 BDB 0 7 5 TS FROM A2D2A er aj 0 7 7 EET 2 74H074 boso 2210 7 BDB 0 7 U40 Peete 2100 00 3 BDBO BDBO 6191 0117 1 DO Qo DO Qo R1 LEDER 8402 025 1 E 88 10 D 6218 7182 12104 13 1 8383 4813 803 R 4 2083 18 03 12105 05 4 1 500 Ben 04 DA Q4 R 8585 13 04 18 06 D6 Hf ERES 05 Q5 05 Q5 Pepe 05 97 07 i 55 SPS CP AE 1420 100H spo G LLL o 45D ow GLK CLK 0833 GLK 4 048 1 RE 74HC374 74HC374 74HC374 74HC378 C55 mes 054 77
30. 41 R149 R150 R261 R267 LANGEM R255 R278 R294 R296 12 S 1 RIO AAA 4 S r 01 00 RCF91K 2 91 5 R123 R291 RCT100K 100K 1 4W 196 R45 R58 R59 R60 R68 R99 RCT10K 10K 1 4W 196 R51 R52 R53 R55 R57 R292 R293 R295 5 RCT10R 1 10R 1 4W RCT113K 113K 1 4W 1 RCT11RO 2 11RO 1 4W 1 R37 R42 RCT180K 180K 1 4 1 8 5 TONEOHM 950 SERVICE MANUAL 8 6 1 1 4W 1 1 1 4W 1 1RO 1 4W 1 200R 1 4W 1 20K 1 4W 1 220K 1 4W 1 24K 1 4W 1 2K0 1 4W 1 430K 1 4W 1 470K 1 4W 1 RVB323 100K Preset 1 SWB143 1 Selector Switch 125 1 PowerTrasfome 177 146 1 Power Transformer 177 5 MECHANICAL KIT CVD155 p 470pF Polypropylene C709 C710 C711 C712 F6 115V F5 F6 230V F5 F6 230V INDIO9 1 FerriteClamp MCA1388 1 EnclosureTop 139 1 Enclosure Bottom 143 1 FrontMoulding 020 MKB127 2 Knob Capgreywihlne 128 2 lt Knob Greypsshon 153 1 Button Round Black MMP107 5 NyonCableTie75mn 5107 17 KS0x6seltap 1 5117 2 MS3xtOPanHd 5163 12 M3x12Csk J 5164 24 2 5175 122 M3Flangenmut 1 5176 2 X KSOx8sellap 142 12 PC
31. 50 THEORY OF OPERATION The TONEOHM 950 consists of the following functional blocks 1 Microvolt Amplifier 2 Trace Amplifier 3 Current source 4 Plane Amplifier and Vector discriminator 5 Vectored Plane Stimulus 6 Drive Source 7 Tone Generator 8 A2D2A 9 Power Supply 10 Microprocessor 11 Front Panel Amplifies attenuates PCB track voltages and is used in conjunction with the internal current source for the calculation of track resistance and current Amplifies and rectifies the low level AC signal from the Trace probe to provide a DC voltage output proportional to magnetic field Provides a range of currents for resistance and non invasive current measurement Amplifies low level plane signals separates vector and magnitude components Provides the four vectored signals for Plane Shorts mode User adjustable constant current DC supply for non invasive current measurement uV measurement Also operates in a c for non contact current tracing Voltage controlled oscillator which provides varying tone proportional to meter reading Analog to digital convertor used for providing microprocessor with data for non invasive current measurement also used for internal calibration and QC Digital to analog converter provides output for tone generator in 2A and 200mA modes and output to front panel meter 5V analog and digital supplies 12 5V floating supply for drive source 4V a c supply
32. Bsupot 155 1 _ CableClip J O 191 2 TitAssemblyleg 193 4 BumperFot 002 MPP198 2 j TitAssembyBase MPP210 1 EC InletBoot 0 O 230 13 Cablete 2 MPP231 2 lnsetCover 154 1 _ j DinSocet5x45 155 1 DinSocket5x60 2 158 11 2 MQX179 1 4mmRedSocket 210 1 X 4mmBlueSoket MQX222 1 S5mmSterePCBJack 5 Pin Din Domino Polarised 224 1 4mm Yelow Socket 225 1 4mmGreenSocket 1 254 1 IEC Inlet Connector MOX314 1 lECFilteredinlet MWP2833 1 X FrontPanelLabel 02 MwP234 1 LCDWindowLabe MWP235 1 RearpanelLabel MWPD1057 1 MWPD1079 1 JjFlexihield O R705 R710 WMAT04 025m GreenYellwwie WMA108 1 nk 8 7 TONEOHM 950 SERVICE MANUAL 197 Speaker Lead A WMA202 Plane Cable Blue WMA305 Plane Drive Cable A 8 8 5 SECTION 9 SCHEMATIC DIAGRAMS TONEOHM 950 SERVICE MANUAL 9 2 This page is intentionally blank
33. D30 or D34 conduct current no longer flows through L1 or L2 the microprocessor registers NO PLANE 08 and turns off K14 This feature will turn off the stimulus at any time it is disconnected while Active Drive Source The Drive Source provides both an 80kHz ac low impedance output for non contact current tracing and an adjustable DC output for non invasive current measurement and microvolt measurement U13 and U19 form a gated oscillator enabled only in TRACE mode Q3 and Q4 provide a low impedance output U13A monitors the output current turning on the front panel DRIVE SOURCE indicator when a current of gt approximately 5mA is flowing U13D and Q4 comprise a protection circuit which cuts off drive to Q3 should the leads be connected to a negative voltage D39 provides protection from positive voltages Tone Generator U20D and Q7 form a VCO whose frequency is proportional to the voltage at TONE GEN or its inverse if INVERT is selected The output of the VCO is made symmetrical by U21B which is also gated by the microprocessor to allow the tone to be turned off in the 20V range and during current auto ranging U64 is a voltage controlled amplifier providing volume adjustment from the front panel U22 provides the audio power output The following controls are applied to the tone generator 20V range gated off by NO 200mA 2A gated off below 10mA approximately and during auto ranging 2mV and 20mV Invert
34. ING BUT NOT LIMITED TO LOSS OF PROFITS OR DAMAGES TO BUSINESS OR BUSINESS RELATIONS WHETHER OR NOT ADVISED IN ADVANCE OF THE POSSIBILITY OF SUCH DAMAGES THE FOREGOING LIMITATIONS SHALL APPLY NOTWITHSTANDING THE FAILURE OF ANY EXCLUSIVE REMEDIES DECLARATIONS DECLARATIONS European Community Directive Conformance Statement Refer to the Operator Manual to determine conformance with European Community Directives TONEOHM 950 SERVICE MANUAL SAFETY WARNING The service instructions contained in this manual are for use by qualified electronic service personnel only WARNING The LIVE and NEUTRAL lines on this unit are BOTH fused When the unit is connected to its supply the opening of covers or removal of panels is likely to expose dangerous voltages GROUNDING This unit must be earthed grounded do not operate the instrument with the safety earth disconnected Ensure the instrument is connected to an outlet with an effective protective conductor terminal earth Do not negate this protective action by using an extension cord without a protective conductor Note This instrument is fitted with S wire grounding type plug designed to fit only into a grounding type power outlet If a special local plug must be fitted to the power cord ensure this operation is performed by a skilled electronics technician and that the protective ground connection is maintained The plug that is cut off from the power cord must be safely disposed of
35. M339 LM339 5A F140 5A R152 777 1K2 9 100K 631 R155 To Loudspeaker 10K 100K JP9 5 1 2 50 200mOHM_THRESHOLD 74 1 4148 C85 ze L 4 u22 C32 To ane Jack R156 on e 3 a pe Blo de T 60 220uF 1 UU qut 0180 MP 1 e 56 E 10 777 R257 1 I mn 77 Hi lt 60mV R142 ise 74HC00 1K2 E 256 Vie C71 10K U29A Y 11 1 10UF U23 U21 Pin7 to 5A Turns tone off lt 60mV in uV 57 REVERSED Fr 74HC04 DD 74HC32 INHIBITREV Polar Intruments Ltd Garenne Park St Sampsons Guernsey Channel Islands Inst i 950 Ime Tone Generator A B C D E 050 nsitivit 5 Sensitivity 74HC374 R191A l2 B174 D53 100 Ganged 5 75 054 SOME
36. Polar Instruments Ltd Garenne Park en TONEOHM 950 SERVICE UAL Fax 44 0 1481 252476 Email mail polar co uk MAN130 201 1 TONEOHM 950 SERVICE MANUAL POLAR INSTRUMENTS LTD HARDWARE WARRANTY 1 Product Warranty Product hardware is warranted to be free from defects in material and workmanship during the Warranty Period as defined below Product hardware is warranted to conform substantially to Polar s then current as of the date of Polar s product shipment published user documentation during the Warranty Period The Warranty Period is twelve 12 months Product support beyond these periods may be available at additional cost consult Polar for details 2 Warranty Claims Polar shall incur no liability under this warranty if the end user fails to provide Polar with notice of the alleged defect during the applicable Warranty Period and within seven 7 days of delivery to end user or if the defect would not have been reasonably apparent on inspection within seven 7 days of its discovery by end user After receiving such notice Polar will notify the purchaser of its designation of one of the following problem resolution methods Return to Factory The allegedly defective goods must be returned to Polar within seven days of Polar s notice and in accordance with Polar s instructions advised at the time Other Polar will use commercially reasonable efforts to repair correct or work around the problem by
37. TOR During the initial ranging and for on track resistances below approximately 25mQ the un calibrated indicator will illuminate Once ranging has taken place the initial injection attenuation settings are held and the current is calculated continuously The 950 will only measure positive conventional current If the probes are reversed the condition will be indicated on the front panel and the display will blank Trace In TRACE mode the 950 uses an inductive pick up to detect an ac current in a faulty track The ac current is supplied from the DRIVE SOURCE leads the detected signal is conditioned by the TRACE amplifier and then switched to the LCD and TONE GENERATOR by U25 sheet 6 and U59 sheet 1 respectively Track Voltage The uV AMPLIFIER conditions the track voltage and sends it to the LCD U25 sheet 6 and to the TONE GENERATOR The tone is disabled on the 20V range Plane Shorts In Plane Shorts mode the 950 uses VECTORED PLANE Stimulus to set up a field pattern on the plane under test the Plane Clip references the short to ground and the voltage measured on the Plane Probe is an a c signal providing both magnitude and position information The PLANE AMPLIFIER and VECTOR DISCRIMINATOR resolve this into a magnitude signal sent to the LCD and TONE GENERATOR and a vector signal for the 4 direction arrows on the front panel 3 2 CIRCUIT DESCRIPTION Detailed Theory of operation Microvolt Amplifier JP11 is the inpu
38. UF 1 56R hd R21 3 1K lt 1 7 S VSHORT PLANE E RELAY 1 gonne ted this way o for thermal match SOURCE K1 R6 y 2 x 5 t U1 R13 7 EM i 708 3 L 100K D7 4 GUARD T 0344 04 R1 470K 1 P _ Xs b OUT 1 4148 1 4148 560 R204 AUF 1 4148 8 GUARD 1 R5 R8 R9 9 063 2 084 1414148 K2 T 1 CLAMP 5A AD Yo 490K1 4 o 2R2 2008 100K o ane R14 8 1N4148 1 4 84 Hi 24K 10 eun 4 TIGA INTEXT 1 24 R205 uu ei 2K 196 208 E V CLKOUT H2 D85 USES 4053 ON 1u 7650 R2 20K 1 id 75K 1 TONE DIAGRAM ava 150K 120R HW D 10 2 4 1000 R12 40 4 5 1 R3 4 LO 1 0 1 086 IN 1N4148 10K 4 gt R4 1RO 57 US8A 120RL_ K4 OHMS gt 2 1N4148 TLC27 079 080 Y R243 U59 1N4148 1N4148 360K 12 GEN NC He T cn R245 x3 246 20K 4 1N4148 aR U58C H yo 47 242 tt Not fitted TLC279 6 T 227 SAU o ma F a B 3V3 150K R239 R240 20K MODE 0 ES rh 20K 200R MODE 1 4052 1 we x Polar Intruments Ltd Garenne Park St Sampsons Guernsey Channel Islands hoe Tie Microvolt Amplifier A B C D E
39. cover rear edge first and remove The main printed circuit board must be removed before the front moulding or feet can be removed 4 1 SECTION 5 LINE VOLTAGE AND FUSE CHANGING WARNING Service of this instrument should only be performed by skilled electronics service personnel There are hazardous voltages inside the instrument when connected to its power supply REMOVE THE POWER CORD before touching any part of the line input circuit Note that high voltages may continue to be present for 2 minutes after power is removed until internal capacitors discharge LINE VOLTAGE SELECTION AND FUSE CHANGING Note When replacing fuses always use the type and rating stated in SPECIFICATIONS Changing the line voltage setting When changing the line voltage it will be necessary to dismantle the instrument as described in Section 4 changes may be made as follows 1 2 3 Remove the two screws in the rear of the cover and lift off lift the rear first In early instruments locate the line selector switch and change to the local line voltage In later instruments remove the gold plated links extract the links with small pliers and replace them in the locations corresponding to the local line voltage Locate the supply fuse 2 fuses in later instruments and replace with the value and rating stated in SPECIFICATIONS Replace the cover Erase the marking on the label on the rear of the instrument and mark in the new voltage
40. e first 180 degrees of the line signal followed by the same signal from top right to bottom left during the second 180 degrees The two halves of the stimulus circuit are identical except for the phase of the inputs which allow the steering diodes D31 D32 D73 D35 to pass current on alternate half cycles Relay K14 allows the microprocessor to turn the stimulus off and on Taking the top circuit as the example 2 and 2A are the outputs of the 4V RMS transformer winding As 2A goes positive D31 conducts and attempts to pass current through L1 F1 through its stimulus lead and return through the lead at the opposite diagonal of the board during this half cycle the other stimulus circuit is inactive As current flows through inductor L1 Hall sensor Q12 detects its presence and the monostable U61A is repeatedly clocked the output of the monostable is OR d with its equivalent in the other stimulus circuit and if either inductor L1 or L2 is NOT conducting NO PLANE DS will be low NO PLANE DS is monitored by the microprocessor in PLANE SHORTS mode When the user presses PLANE to activate the mode the 950 will turn on relay K14 on if no current is detected in L1 or L2 K14 will be turned off 3 4 CIRCUIT DESCRIPTION In order to protect semiconductor devices D30 and D34 are Schottky diodes which conduct if the stimulus voltage attempts to rise above approximately 0 4 volts This will occur if the stimulus is not connected correctly As
41. heck the HEPLACEMENT PAHTS list before ordering spares Microprocessor The system is based on a Z80 U35 which is reset and shut down by controller U38 4MHz Resonator X1 is divided by 2 to produce a 2MHz system clock Firmware is held in ROM U36 and U34 provides 2K of utility RAM The remainder of the bus related circuits provide 1 for controlling or monitoring the instrument U43 and U37 provide appropriate address decoding Front Panel Schematics 1 and 2 The digital part of the front panel is an extension of the processor system providing a keyboard row and column decoder U49 and U52 and other ports for LED drive U57 and associated components form the drive for the Plane Direction arrows and come under the control of the Vector discriminator circuit D76 is a backlight array for the LCD whilst U53 provides display A2D conversion and LCD Drive U56 provides logic level conversion for decimal points and U54 is the LCD 3 6 SECTION 4 DISMANTLING INSTRUCTIONS WARNING Service of this instrument should only be performed by skilled electronics service personnel There are hazardous voltages inside the instrument when connected to its power supply REMOVE THE POWER CORD before touching any part of the line input circuit Note that high voltages may continue to be present for 2 minutes after power is removed until internal capacitors discharge Removing the cover Undo the two screws in the rear of the cover then lift the
42. means of telephone support or other means reasonably determined by Polar Polar shall incur no liability under this warranty if Polar s tests disclose that the alleged defect is due to causes not within Polar s reasonable control including alteration or abuse of the goods Under the Return to Factory alternative if a Product is determined not to be defective or to have a defect due to causes not within Polar s reasonable control Polar reserves the right to apply a processing charge 3 Damage in Transit End user must notify Polar and the carrier of any claim for damage in transit within two 2 days of receipt of the damaged merchandise Failure to do so may result in the carrier and or Polar refusing to accept liability in which case end user must pay the purchase price as if the hardware had been delivered without damage 4 Polars Liability Polar s liability and end user s sole and exclusive remedy shall be limited to the express remedies set forth in this Polar Hardware Warranty 5 Disclaimer of Warranties POLAR MAKES NO OTHER WARRANTIES EXPRESS IMPLIED OR STATUTORY REGARDING PRODUCTS ALL OTHER WARRANTIES AS TO THE QUALITY CONDITION MERCHANTABILLITY FITNESS FOR A PARTICULAR PURPOSE OR NON INFRINGEMENT ARE EXPRESSLY DISCLAIMED 6 Limitation of Liability POLAR SHALL NOT BE RESPONSIBLE FOR DIRECT DAMAGES IN EXCESS OF THE PURCHASE PRICE PAID BY THE END USER OR FOR ANY SPECIAL CONSEQUENTIAL INCIDENTAL OR PUNITIVE DAMAGE INCLUD
43. n ACTIVE illuminates the A2D is calibrated 4 PUSH 24 The 950 will beep and enter the 20V Range Resistance Calibration 1 SELECT the 20 range Place the probes across the 1 resistor ADJUST R713 R30 for instruments below S N 012213 for 1 0000 reading 3 Counts TONEOHM 950 SERVICE MANUAL Current range adjustment Serial N 012213 and above below this Serial N there is no adjustment Select the 200mA range Drive source control fully clockwise Connect the drive source and the DVM across the high tolerance 10 resistor Note the DVM reading Apply the needle probes across the resistor and adjust R 30 for the same reading as the DVM 5 counts Current offset calibration Version 8 firmware and above Qv 6 Set the current limit to MINIMUM switch the supply ON Select 2A on the 950 Connect the power supply across the 100mQ resistor Adjust the current limit to 1 6A Using the Needle Probes measure across the 100mQ resistor CHECK for 1 44 to 1 76A on the 950 display Version 8 firmware and above main board version 5 and above Select the most accurate 1 6A reading by optionally placing a jumper on one of the 4 locations adjacent to U46 No jumper is the mid setting H fixes slight under reading HH corrects large under reading L fixes slight over reading and LL corrects large over reading Version 8 firmware main board version 4 or below Connect a 20 way integra
44. nal to detected magnetic field strength TRACE SENSITIVITY Capable of detecting current flow with 2000 resistance across Drive Source PROBE VOLTAGE 600mV maximum in 200mA 2A Not applicable in TRACE INJECTION CURRENT 250mA maximum Not applicable in TRACE INDICATION Tone and meter in all ranges PROBE PROTECTION Momentary contact up to 250V in 200mA 2A Not applicable in TRACE Track Voltage RANGES 2mV 20mV 20V ACCURACY AA HAB INPUT RESISTANCE 1200 in 2mV 20mV 1MQ in 20V INDICATION Meter in all ranges Tone in 2mV 20mV PROBE PROTECTION Momentary contact up to 250V in 20V 30V in 20mV 2mV Plane Shorts INDICATION Tone uncalibrated meter and fault direction arrows SENSITIVITY Adjustable for differing plane resistance Capable of detecting shorts up to 200 Plane Stimulus OUTPUT VOLTAGE 550mV maximum Active only when PLANE SHORTS is ACTIVE and outputs are connected to a plane OUTPUT CURRENT 700mA RMS maximum PROTECTION Each output separately fused 5A Fast viii SPECIFICATIONS Drive Source OUTPUT VOLTAGE 0 to 550mV adjustable AC in TRACE DC in all other ranges PROTECTION Protected to 30V ENVIRONMENTAL OPERATING CONDITIONS The instrument is designed for indoor use only under the following environmental conditions Altitude Up to 2000m 5 C to 40 C ambient Relative humidity RH 80 maximum at 31 C derate linearly to 50 at 40 C Mains borne transients
45. ps into the solder The reading should be within 496 Readings vary with the pressure applied to the probes Press TRACE and connect the Drive Source leads across 200 Q resistor Turn the DRIVE SOURCE knob fully clockwise Hold the Current Trace Probe tip near to one of the Drive Source leads and align it for maximum response Check that the display shows 20 or more Connect the Blue and Yellow Stimulus lead together Press PLANE twice check for the warning bell and that the instrument returns to Standby Leave leads connected Connect the Red and Green Stimulus lead together Press PLANE once Check for ACTIVE LED Connect the red and black Drive Source leads across a 0 1 resistor Attach the Plane Clip to the black Drive Source lead Probe the other end of the resistor with the probe 20 21 22 23 24 25 26 PERFORMANCE CHECK Slowly turn the DRIVE SOURCE from minimum to maximum i e clockwise As the control is rotated check that initially all direction arrow LEDs are on then the upper LED only then all LEDs are off At the same time the tone goes from high to low then off Reverse the connections to the Plane Probe and Clip Rotate DRIVE SOURCE from maximum to minimum i e anti clockwise As the control is rotated check initially for no arrows or tone then rising tone and bottom arrow on finally all arrows on Disconnect the Red and Green Stimulus lead PLANE should automatically ring warning bell
46. ropyl alcohol IPA may be used Do not spray cleaners directly onto the instrument Technical Support For technical support contact your local Polar Instruments distributor or Polar Instruments Ltd at the address at the front of this manual Instrument repair If it becomes necessary to repair the instrument in the first instance contact the Polar Instruments distributor in your country In case of difficulty contact Polar Instruments Ltd at the address at the front of this manual Do not send the instrument until shipping instructions have been received from the repairer 7 1 SECTION 8 REPLACEMENT PARTS To ensure correct parts are supplied orders for replacements should include the following details Instrument type Instrument serial number Firmware version if applicable Circuit reference if applicable and description Note Parts marked with an asterisk have been subject to modification in later instruments Safety critical parts listed in bold type must be replaced with parts obtained from Polar Instruments Ltd or your Polar Instruments distributor to ensure continued safe operation 8 1 TONEOHM 950 SERVICE MANUAL FRONT PANEL KIT Description ICA130 4070 U55 40005 4 LED116 10 LED Yellow D53 D55 D56 D57 D58 D59 D60 D61 D62 D63 LED117 LED Green 154 12 ButonCap 200 16 38mmSpaer 2
47. selected U20A and B detect a band of 40uV and turn off the tone in this region more negative than 40uV oscillator U17D runs causing a unique pulsing tone Reversed signal also taken to front panel led e resistance ranges Invert is off and at low readings U20A goes high allowing U17D to oscillate and cause a pulsing tone at low readings TRACE as 2mV A2D2A Hefer to A D Converter Schematic 026 and associated logic interface the uV AMPLIFIER with the microprocessor allowing it to read the 12 bit conversion in a high and low order byte The data is used for current calculation and system calibration U28 8 bit D2A convertor allows the computed current to be sent to the TONE GENERATOR and the LCD U25 is controlled by the processor to route analog signals from the main modules to the display Power Supply 032 and U33 provide analog 5 Volt supplies LK7 or 8 allow the Phase of the line signal to be selected in case of transformer phase change This will affect left and right arrows in PLANE SHORTS U31 provides a separately regulated 5V supply for the digital systems and relay drive U30 Provides a floating 5Volts for the drive source 2A and 2A is a floating 4V RMS supply for the Vectored Stimulus 3 5 TONEOHM 950 SERVICE MANUAL Note that from Serial N 011265 a line filter was fitted and the line voltage selector switch was replaced by links The power transformer has undergone several changes c
48. sons E Guernsey Channel Islands Inst Title 950 Input Sockets A B C D E C D E ALO AIO WR A A Dio 035 780 036 034 214 1 m 0 0 AQ 0 m AQ 8 m 2 po pro 7 45D DS POTI MBEO 54 mago RE PARE BEN QUADRANT L gt m sSssm 8 WR A 38 04 HE 2 M Da H 4 ARROW OFF D gt 6 4 8 6 16 7 RD AG 06 D 4 28d A7 HAEA AD 07 DAN 07 BN 184 HALT A NTN AR 9 Ali 9 0 10 10 z ui 6 AD INT A13 AE AR A13 OE 5D 8 NMI A14 A14 o 0 m d RESET Sd Al 0 6116 4 DO RD RP2 DO 5 16 Big Di VPP U43 8 22K QUADRANT 0 gt d 17 18 BUSAK ES 8 D3 N 7 22 CLK Da 50 108 2 9
49. t connection from the probe sockets Relays K1 2 and provide 1 10 and 1000 attenuation setting for the main Amplifier U1 K4 provides a switchable 1200 input resistance used in 2mV and 20mV 01 is a low offset voltage chopper stabilised amplifier with gains of x10 or x100 selected by the analog switch U24 on the Tone Generator schematic The network on the output of U1 provides an idealised response for the tone generator HI and LO are the calibrated outputs to the front panel meter via analog switch U25 on sheet 6 U59 and associated components provide a second nonlinear amplifier for use in TRACE PLANE 200mA and 2A modes Trace Amplifier Refer to Microvolt Amplifier schematic The DRIVE Source provides PCB tracks with an 80 approximately current this is detected by the Trace Probe The low level signal is first amplified and filtered by U2B further amplification and conditioning is provided by nonlinear amplifier U2A the a c signal is then rectified and smoothed by active rectifier U2D after buffering and attenuation U25 A D Converter schematic directs the output to the front panel meter Current Source Hefer to A D Converter schematic The current source provides a range of known dc currents for resistance and non invasive current measurement The loop formed by U5A U62A Q2 D13 and associated components provide a low impedance 56mV 0 56V approximately source The microprocessor is both able to
50. ted circuit test clip to U46 Shorting Pin 17 to Gnd corresponds to HH 14 H 13 LL 8 L No connection is nominal setting Once the best setting is established solder a link from the appropriate pin if any to ground Version 7 firmware and below offer no fine adjustment Current Trace 1 2 3 2 2 Connect Trace Drive Source Probe Push TRACE Adjust the volume as desired short the drive source leads together and turn the drive source to MAXimum While holding the probe against the Drive Source lead ADJUST R94 for the highest displayed reading 500 Move the probe away from the Drive Source leads CHECK Tone turns off and displayed reading is less than 25 ADJUSTMENT PROCEDURE Plane Shorts 1 CONNECT the 4 Plane Stimulus leads BLUE to YELLOW and RED to GREEN 2 Push PLANE twice to enter ACTIVE mode 3 CONNECT the Plane Clip to the Plane Probe Adjust R85 for a reading of 00 0 3 counts Ser N 012213 up Adjust R716 located near U18 behind copper shield for minimum or most negative reading Re adjust R85 for 00 0 3 counts 4 Reduce the Variac to 190V 240V instruments 95V 120V instruments 85V Japanese instruments 5 Check that PLANE remains ACTIVE 6 Remove the Green clip from the demo board and check the 950 goes to standby Reconnect the clip and select ACTIVE 7 Repeat for the yellow clip 8 Disconnect all probes 2 3 SECTION 3 CIRCUIT DESCRIPTION TONEOHM 9
51. ter A B C D E A 23222822202 B D 45UREG 1 USES 4053 ON TONE GENERATOR DIAGRAM R45 R46 100 1 1 196 5A U62A 015 016 t 1272 R46 R272 R273 L lt sey s6mv R45 1M1 1K 1R 100 1 1 1 20 lt 3 080 S 22u Q2 war MJE350 ee R713 gt x 05 Boards Ohms Adjust Current 10K 5f and later R30 56mV gt C To USA Pin 3 10 Ohms Adjust 021 400V 56 R33 100 I R31 R31 D14 R32 10 8K2 R712 bi 8 2 x 7 3 U628 R287 1 lt gt is 200R Adjustment up to S No 012212 x L272 po R276 R277 i NE 1K 18 R274 1 1 C E 22 VW RELAY Kelvin Connected D88 94 may be omitted when D
52. tion and referred to qualified service personnel Protection may be impaired if for example the instrument Shows signs of physical damage Fails to operate normally when the operating instructions are followed Has been stored for prolonged periods under unfavourable conditions Has been subjected to excessive transport stresses Has been exposed to rain or water or been subject to liquid spills CAUTION Electrical Isolation Always disconnect the board under test from the local mains supply including ground before using this instrument Static Sensitive Devices This unit contains Static Sensitive Devices Static discharge can damage some electronic components Care must be taken when handling these components Observe appropriate precautions to avoid damage vii TONEOHM 950 SERVICE MANUAL SPECIFICATIONS Track Resistance RANGES 200m0 20 2000 20KQ Instruments with serial numbers below 005975 have a 2 range instead of 2000 ACCURACY 6 in 200MQ 5 in 20 4 in 2000 5 in 20KQ RANGE High sensitivity uncalibrated Approximately 40m4 full scale PROBE VOLTAGE INDICATION Tone and meter in all ranges PROBE PROTECTION Momentary contact up to 250V Track Current RANGES 200mA 2A TRACE ACCURACY 15 in 200mA 2A for track resistance between 25100 and 500 Reading proportional to current when UNCALIBRATED LED is lit UNCALIBRATED LED lit during ranging Reading in TRACE is proportio
Download Pdf Manuals
Related Search