SERVICE Manual
Contents
1. 3 1 4 Disassembly and Reassembly 4 1 Replacement of Magnetron M otor Assembly and Lamp Remove the magnetron including the shield case permanent magnet choke coils and capacitors all Cover Air Thermo S W of which are contained in one assembly Lamp 1 Disconnect all lead wires from the magnetron and lamp 2 Remove a screw securing the magnetron supporter BKT Mountain _ Remove the magnetron supporter Je Remove the air cover Remove screws securing the magnetron to the wave guide Take out the magnetron very carefully Remove screws from the back panel Take out the fan motor Remove the oven lamp by rotating to pull out from hole of air cover When removing the magnetron make Magnetron sure that its antenna does not hit any V Capacitor adjacent parts or it may be damaged NOTE2 When replacing the magnetron be sure to remount the magnetron gasket in the correct position and make sure the gasket is in good condition OT e en Eg H V Trans 4 1Replacement of High Voltage Transformer 1 Discharge the high voltage capacitor 2 Disconnect all the leads 3 Remove the mounting bolts 4 Reconnect the leads correctly and firmly H V Trans Samsung Electronics 4 1 Disassembly and Reassembly 4 3 Replacement of Door Assembly 4 3 1 Removal of Door Assembly Remove hex bolts securing the upper hinge and lower hinge Then remove the door assembly2. 4 Filament Terminals j Jj y A 1 1 f m y Secondary N primary pampo Terminal Terminals Terminals Resistance 1 2 Input 12010 3 4 Output 7V 4 3480 5 6 Outputl7V 21729 agnetron Antenna bw ef Gasket Plate C 5 lap Y m Cooling Fins Alignment and Adjustments 5 4 High Voltage Capacitor 1 Check continuity of the capacitor with the meter set at the highest resistance scale 2 Once the capacitor is charged a normal capacitor shows continuity for a short time and then indicates 9MQ 3 A shorted capacitor will show continuous continuity 4 An open capacitor will show constant 9MQ 5 Resistance between each terminal and chassis should read infinite 5 5 High Voltage Diode 1 Isolate the diode from the circuit by disconnecting its leads 2 With the ohm meter set at the highest resistance scale measure across the diode terminals Reverse the meter leads and read the resistance A meter with 6V 9V or higher voltage batteries should be used to check the front to back resistance of the diode otherwise an infinite resistance may be read in both directions The resistance of a normal diode will be infinite in one direction and several hundred KQ in the other direction 5 6 Main Relay and Power Control Relay 1 The relays are located on the PCB Ass y Isolate them from the main circuit by disconnecting the leads 2 Oper
3. R CARBON 1Kohm 596 1 8W TP 1 8x3 2mm R CARBON 2 2Kohm 5 1 2W AA TP 3 3x9mm R CARBON 3 9Kohm 5 1 8W AA TP 1 8x3 2m R CARBON 51ohm 5 1 4W AA TP 2 4x6 4mm R CARBON 6200hm 5 1 8W AA TP 1 8x3 2mm R M ETAL OXIDE S 100hm 5 2W AA TP 4x12m C CERAM IC M LC AXIAL UP050F104Z 100N F 480 C AL 15A1ANB107M AN 100UF 20 10V GP 6 3X C AL CESSL1C220M 0511AA 22UF 20 16V GP 5 C AL 1SA1CNBA477M 470UF 20 16V GP 10X12 C AL 1SG1VFB477M 470UF 20 35V GP 10X1 RESONATOR CERAM IC KBR 4 19M 4 19M HZ 0 5 BK RELAY POW ER OM 1F 5 124LM 24V 21 8M A 17A RELAY M INIATURE V24 KT 24V 12 5M A 5A 1F CONN ECTOR FPC FC PIC FCZ254 085 L BLK CONNECTOR HEADER 1W ALL 3P 1R 3 96mm S TRA CONN ECTOR HEADER SM W 250 03 W HT BOX 3P 1R R CARBON RD 1 2 T S 331 J C CERAM IC CC OA CH 50V T 220 3 5X1 9 U TR W RESISTOR KSR1005 300M W 100M A 50V TR W RESISTOR KSR2005 300M W 100M A 50V DIODE ZENER TZP5 1B 5 1 5 7V 40M A T 1W DIODE ZENER TZP7 5B 7 5 8 4V 40M A T 1W CONNECTOR W AFER YW 396 04V WHT LED DISPLAY LTC4638GKC GRN 12 30 48 2X22 38 IC M CU KS57C0004 64 DIP M 745 2N D W LED EURO IC KA7533 DIP IC DRIVE UDN6118A DIP TRANS L V SLV 745E 230V 50HZ AC17 7V BUZZER CBE2220BA STICK WIRE SO COPPER PIO 6 SN T 52M M PIN EYELET ID2 1 002 5 L3 0 SN BSP T0 25 PRP DH ANP a RO pN R04 07 12 15 22 R0
4. 4 3 2 Removal of Door C Insert flat screwdriver into the gap between Door E and Door C to remove Door C Be careful when handling Door C because it is fragile 4 3 3 Removal of Door E Following the procedure as shown in the figure insert and bend a thin metal plate between Door E and Door A until you hear the tick sound 1 Insertion depth of the thin metal plate should be 0 5mm or less 4 3 4 Removal of Key Door amp Spring Remove pin hinge from Door E Detach spring from Door E and key door Upper Hinge Lower Hinge Screws Door E Key Door Spring Samsung Electronics Disassembly and Reassembly 4 3 5 Reassembly Test After replacement of the defective component parts of the door reassemble it and follow the instructions below for proper installation and adjustment so as to prevent an excessive microwave leakage 1 When mounting the door to the oven be sure to adjust the door parallel to the bottom line of the oven face plate by moving the upper hinge and lower hinge in the direction necessary for proper alignment 2 Adjust so that the door has no play between the inner door surface and oven front surface If the door assembly is not mounted properly microwave energy may leak from the space between the door and oven 3 Do the microwave leakage test 4 4 Replacement of Fuse m Disconnect the oven from the power so
5. 705 TEST PROCEDURE 40 320W 13 sec 17 sec 50 400W 16 sec 14 sec OPERATING FREQUENCY 2 450M Hz 60 480W 19 sec 11 sec MAGNETRON OM 75SH 31 10 560W 22 sec 8 sec COOLING M ETHOD COOLING FAN MOTOR me on DU dh 9096 720W 28 sec 2 sec OUTSIDE DIM ENSIONS 489 W x 275 H x 371 D 100 800W 30 sec 0 sec 2 2 Comparison Chart M ODEL FEATURE M757 M ORE LESS AUTO COOK DISH AUTO DEFROST TIME COOK POWER LEVEL INSTANT COOK MEMORY O BOOST CHILD LOCK CLOCK 5 GRILL COMBI Samsung Electronics 2 1 3 Operating Instructions 3 1 Control Panel Decongel Auto con amp uty CA S Auto Auto Deforst Button 44 Reheat amp Cook Serving Size fA Instant Cook Button SEN E Selection Button eum e Q Q Or Power Level Selection Button Clock Setting Button C Deodorization Botton Memory Feature Button pr t Annulation D part Stop Cancel Q9 X Om Start Button M757 3 2 Features amp External Views Door Ventilation Slot Light Dial Knob Time T Weight and Auto Cook Code Selection Botton Safety Interlock Holes Control Panel Open Door Push Button 2 Door Latches A S 1 SAMSUNG T 200 357mm T 489mm 371mm Samsung Electronics
6. Rise The result should exceed 65 Cooking Tray Samsung Electronics 5 3 Alignment and Adjustments 5 8 Procedure for Measurement of Microwave Energy Leakage 1 Pour 275 e15cc of 20 25 68 a965 water ina beaker which is graduated to 600cc and place the beaker in the center of the oven 2 Start to operate the oven and measure the leakage by using a microwave energy survey meter 3 Set survey meter with dual ranges to 2 450MHz 4 When measuring the leakage always use the 2 inch spacer cone with the probe Hold the probe perpendicular to the cabinet door Place the spacer cone of the probe on the door and or cabinet door seam and move along the seam the door viewing window and the exhaust openings moving the probe in a clockwise direction at a rate of 1 inch sec If the leakage testing of the cabinet door seam is taken near a corner of the door keep the probe perpendicular to the areas making sure that the probe end at the base of the cone does not get closer than 2 inches to any metal If it gets closer than 2 inches erroneous readings may result 5 Measured leakage must be less than 4mW after repair or adjustment M aximum allowable leakage is 5mW cnv 4mW cm is used to allow for measurement and meter accuracy 5 9 Check for Microw ave Leakage 1 Remove the outer panel 2 Pour 275 15cc of 2045 C 68 9 F water in a beaker which is gr
7. of microwave due to its characteristics W rap thinner parts of the food with aluminum foil Use plastic wrap or cover with a lid Stir once or twice while cooking foods such as soup cocoa or milk Noise from the turntable motor when it starts to operate Noise may result from the motor Replace turntable motor Samsung Electronics 7 Exploded Views and Parts List 7 1 Exploded Views 7 1 Samsung Electronics Exploded Views and Parts List 7 2 Main Parts List Ref No Parts No Description Specification Q ty Remarks 1 DE70 30116B PANEL OUTER SECC T0 6 W 351 7 L1014 7 WHT CO 1 M 2 DE63 90035A CUSHION RUBBER DFA 20 2 W 190 L100 BLK 1 M 3 DE39 20054D ASSY POWER CORD KKP 4819D B206 250V6A L1 1 M 4 DE39 40537A ASSY WIRE HARNESS A 230V50HZ M 945 SAW 1 M 5 DE91 40093A ASSY NOISE FILTER SN E10D 250V 10A 1 M 6 DE31 30031A FAN M OTOR SM F745EA 230V 50HZ ASSY FAN MO 1 M 7 DE47 20009A THERM OSTAT CS 7SA 160 60 187Y 250V7 5A 1 1 M 8 DE03 30029A M AGNETRON OM 75SH 31 ESS 1 A M 9 DE93 20020A ASSY BODY LATCH RE 43B 90B 1 M 12 DE71 60010A COVER AIR PP TB53 T1 7 WHT 64G M 745 1 M 10 4713 001004 LAM P INCANDESCENT 230V 40W ORG 25x 1 M 12 DE71 60010A COVER AIR PP TB53 T1 7 WHT 64G M 745 1 M 13 DE27 10020A COIL M C CHOKE TC 101 1 M 15 DE26 10121B TRANS H V SHV 745EC1 230V 50HZ KEC 2230V 3 1 A M 16 DE61 50106A BRACKET HVC SECC T0 8 W 31 L125 8 1 M 17 2501 0010
8. 0 10082A SCREW A M 4112 25 TOOTHED 2 BD LAT DE60 10082A SCREW A M 4 L12 25 TOOTHED 1 CV AIR DE60 10082A SCREW A M 4112 25 TOOTHED 2 M O FAN DE60 10082A SCREW A M 4 L12 25 TOOTHED 5 PN OUT DE60 10098A SCREW ASSY TAPTITE PH TC M 4X8 SW RCH18A ZPC2 1 CV TCO DE60 10098A SCREW ASSY TAPTITE PH TC M 4X8 SW RCH18A ZPC2 2 M DRIV DE60 10098A SCREW ASSY TAPTITE PH TC M 4X8 SW RCH18A ZPC2 2 G TCO DE60 20063A BOLT FLANGE M 4 10 ZPC3 YELM SWR 2 HI LOW DE60 20063A BOLT FLANGE M 4 10 ZPC3 YELM SWR 2 HI UPP 7 4 Samsung Electronics 8 P C B Diagrams 8 1P C B Diagrams Samsung Electronics 8 1 P C B Diagrams 8 2 P C B Parts List Parts No Description Specification Q ty Remarks 0401 001002 DIODE SWITCHIN G 1N 4148M 100V 200mA 500mW 1 D04 08 13 0402 000559 DIODE RECTIFIER D4G 400V 1A T 1 6 D01 03 05 07 0501 000283 TR SMALL SIGNAL KSA539 Y PNP 400mW TO 92 1 TROL 0501 000388 TR SM ALL SIGNAL KSC815 Y NPN 400mW TO 92 1 TRO3 2001 000290 R CARBON 10Kohm 5 1 8W AA TP 1 8x3 2mm 12 R08 11 14 16 17 19 20 23 25 2001 000429 2001 000446 2001 000613 2001 000841 2001 000904 2003 000471 2202 000780 2401 000247 2401 000914 2401 001362 2401 001412 2802 000143 3501 001014 3501 001016 3708 000523 3711 000203 3711 000881 A1000 0620 A1100 1049 A4060 0008 A4060 0009 A4106 0154 A4106 0204 A6010 0461 DE07 20126A DE09 30487A DE13 20009A DE13 20033A DE26 20146A DE30 20016A DE39 60001A DE60 60012A
9. 3 R13 18 R26 32 R21 R01 C05 06 09 10 C03 C04 C02 C01 XTL1 RYO1 RY02 03 CN04 CN01 CN 03 R02 C07 08 TR02 04 07 09 08 2002 2001 CN02 LED1 01 A 02 BUZ1 J 01 17 22 28 E01 08 8 2 Samsung Electronics 9 Schematic Diagrams 9 1 Schematic Diagrams ASSY NOISE FILTER MGT CAVITY PRIM ARY pov ce UP NCC ICO etd BRN BLK M ML BLK E TT E u 230V ut 50Hz gt mH 1 pig MONITOR H V FUSE gt SWITCH ee LE Pay VOLTAGE 1 5 FREG he YEL N 1 BLU BLU 1 i POWER RELAY NOE zu m 1 INPUT 230V M AGNETRON DOOR g 2 DOOR OFEN MAIN INRUSH POWER SENSING y SE 3 LAMP ON LVT RELAY RELAY RELAY SWITCH d B ald SYMBOL COLOR 4 P C B PATTERN me e li BRN BROWN 5 m P CBIN OUT c Rd o
10. 36 C OIL 950nF 2100V BK 35x54x85 20mm 1 M 18 DE59 40001A DIODE H V HVR 1X 32B 12 1 M 19 DE91 70061B ASSY H V FUSE THV060T 0750 H 5KV0 75A RE 1 M 20 DE61 40017A FOOT PP A353 M W5630T 2 M 21 DE31 10154A M OTOR DRIVE M 2H 49ZR02 ST 16 21V 5 6 1 M 22 DE80 10003A BASE PLATE SGCC1 Z 8 W 340 L550 M 745 1 M 23 DE47 20033A THERM OSTAT PW 2N 80 70 125V15A 250V7 5A 1 M 24 DE71 60011A COVER M GT PP T2 0 WHT M 745 1 M 25 DE61 80004A HINGE LOW ER SCP1 T2 3 ZN COATING BLK 1 M 26 DE61 80005A HINGE UPPER SCP1 72 3 BLK ZN COATING 1 M 27 ASSY DOOR HANDLE WHT M 757 M 737 SKW 1 Ae M 28 ASSY CONTROL BOX 230V50HZ M 757 SDW SAW S 1 Ae M 29 DE74 20102B TRAY COOKIN G GLASS T5 0 PI288 780G M 745 1 M 30 DE92 90436A ASSY GUIDE ROLLER M W 4370W 1 M 31 DE67 60002A COUPLER PPS 5GR BRN M 97G45 1 M 32 DE63 90065F CUSHION LAM P PUT FOAM 140 W 10 L290 SM2 1 Option Parts 7 2 A Warning A Electrostatically Sensitive Devices Samsung Electronics Exploded Views and Parts List 7 3 Door Parts List Ref No Parts No Description Specification Q ty Remarks D1 DE64 40272A DOOR A ABS HR 0370D WHT M 737 M 757 1 D2 DE67 20164A SCREEN DOOR B ACRYL T1 5 W 234 2 L362 5 M 73 1 D 3 DE64 40273A DOOR SUB ABS HR 0370D W HT CE757G 1 D4 DE92 50126B ASSY DOOR E COATING BLK CE745G 1 D5 DE64 40008B DOOR C PP T1 5 BLK CE745G 1 D6 DE01 00003A FILM DOOR PE FI
11. Ad DM BLU BLUE ORG ORANGE POINT el RED RED E ASSY MAIN P C B WHE CWHITE 8 8 8 BLK BLACK PRIMARY DOOR ERE d en n SWITCH Y G YELLOW GREEN MAGNETRON HIGH VOLTAGE DIODE TO CHASSIS ml Li A HIGH VOLTAGE CAPACITOR RED RED A RED H V FUSE BRN SYMBOL COLOR m ORG ORANGE RED BRN BROWN au RED RED BLU BLUE HIGH VOLTAGE TRANSFORM ER Samsung Electronics 9 1
12. E MICROWAVE OVEN M757 27 SER VICE Manual MICROWAVE OVEN CONTENTS 1 Precaution 2 Specifications 3 Operating Instructions 4 Disassembly and Reassembly gt 5 Alignment and Adjustments 5 4 6 Troubleshooting SAMSUNG 7 Exploded Views and Parts List 8 PCB Diagrams 9 Schematic Diagrams SEI 1 Precaution Follow these special safety precautions Although the microwave oven is completely safe during ordinary use repair work can be extremely hazardous due to possible exposure to microwave radiation as well as potentially lethal high voltages and currents 1 1 Safety precautions A m II 99 B e N 95 39 repairs should be done accordance with the procedures described in this manual This product complies with Federal Performance Standard 21 CFR Subchapter J DHHS Microwave emission check should be performed to prior to servicing if the oven is operative If the oven operates with the door open Instruct the user not to operate the oven and contact the manufacturer and the center for devices and radiological health immediatly Notify the Central Service Center if the microwave leakage exceeds 5 mW cm Check all grounds Do not power the MWO from a 2 prong AC cord Be sure that all of the built in protective devices are replaced Restore any missing prot
13. LM_T0 15 W143 1265 M745 1 D7 DE64 40264A DOOR KEY POM HANDLE T 25 W51 L40 BLK R 1 e D 8 DE61 70033A SPRING KEY ES HSWR10 P10 6 06 0 122 3 BL 1 D 9 DE02 00031A TAPE DOUBLE FACE ACRYL 70 26 W 15 WHT A 2 1 7 4 Control Parts List Ref No Parts No Description S pecification Remarks Cl DE91 10430A ASSY P C B M AIN 230V50HZ NS LED M 757 EURO 1 C2 DE72 70178A CONTROL PANEL ABS HR 0370 W HT M 757 DSW SAW 1 C 3 DE67 40147A WINDOW DISPLAY ACRYL SM OG M 757 CE757G 1 e C4 DE66 20183A BUTTON SELECT B ABS HR 0370D W HT M 757 1 C5 DE66 20185A BUTTON SELECT A ABS WHT M 757 CE757G 2 C 6 DE66 20184A BUTTON SELECT C ABS HR 0370D WHT M 757 SKW 1 A C7 DE67 10128A KNOB ABS HR 0370D WHT 757 CE757G 1 7 5 Body Latch Parts List Ref No Parts No Description S pecification Q ty Remarks B1 DE66 40001A LATCH BODY POM F20 02 40GR NTR 1 B2 3405 000178 SW ITCH M ICRO VP 533A OF PS T85 250V 15A 2 B3 3405 000175 SW ITCH M ICRO VP 531A OF T85 250V 15A 20 1 B4 DE66 90001A LEVER SW ITCH P O M F20 02 2 6 NTR 2ND W 1 B5 DE72 60106A GUIDE S W ABS BLK 1 Samsung Electronics 7 3 7 6 Standard Parts List Parts No Description Specification Q ty Remarks DE60 10012A SCREW TAP TITE TH 3 M 4 L10 SWR10 ZPC2 TOO 1 N F EA DE60 10012A SCREW TAP TITE TH 3 M 4 L10 SWR10 ZPC2 TOO 4 P C EA DE60 10080A SCREW W ASHER M 5 L12 25 4 MGT DE60 10080A SCREW W ASHER M 5 L12 25 4 TNS HV DE60 10082A SCREW A M 4112 25 TOOTHED 2 B PLTE DE6
14. aduated to 600cc and place the beaker in the center of the oven 3 Start the oven at the highest power level 4 Set survey meter dual ranges to 2 450MHz 5 Using the survey meter and spacer cone as described above measure arnear the opening of magnetron the surface of the air guide and the surface of the wave guide as shown in the following photo but avoid the high voltage components The neading should be less than 4mW cm 5 10 Note on Measurement 1 Do not exceed the limited scale 2 The test probe must be held on the grip of the handle otherwise a false reading may result when the operator s hand is between the handle and the probe 3 When high leakage is suspected do not move the probe horizontally along the oven surface this may cause damage to the probe 4 Follow the recommendation of the manufacturer of the microwave energy survey meter 5 11 Leakage M easuring Procedure 5 13 1 Record keeping and notification after measurement 1 After adjustment and repair of a radiarion preventing device make a repair record for the measured values and keep the data 2 If the radiation leakage is more than 4 mW 8x after determining that all parts are in good condition functioning properly and the identical parts are replaced as listed in this manual notift that fact to SAMSUNG ELECTRONICS ITALY S P A VIA F LLI GRACCHI 48 20092 CINISELLO BALSAMO MILAN ITALY 5 13 2 At least once a year have the microwave energy s
15. an program but timer does not start 1 Open or loose wiring of secondary interlock switch 2 Off alignment of primary interlock 3 Defective secondary interlock S W Adjust door and interlock switches Microwave output is low Oven takes longer time to cook food 1 Decrease in power source voltage 2 Open or loose wiring of magnetron filament circuit Intermittent oscillation 3 Aging of magnetron Consult electrician Fan motor tums on when plugged in Loose wiring of door sensing switch Check wire of door sensing switch Oven does not operate and return to the plugged in mode Defective Ass y PCB Replace PCB main Loud buzzing noise can be heard 1 Loose fan and fan motor 2 Loose screws on H V Transformer 3 Shorted H V Diode Tighten screws of fan motor Tighten screws of H V Transformer Replace H V Diode Turntable motor does not rotate 1 Open or loose wiring of turntable motor 2 Defective turntable motor Replace turntable motor Oven stops operation during cooking 1 Open or loose wiring of primary interlock switch 2 Operation of thermal cutout M agnetron Adjust door and latch switches Sparks 1 M etallic ware or cooking dishes touching on the oven wall 2 Ceramic ware trimmed with gold or Silver powder also causes sparks Inform the customer Do not use any type of cookware with metallic trimming Uneven cooking Uneven intensity
16. ate the microwave oven with a water load in the oven Set the power level set to high 3 Check continuity between terminals of the relays after the start pad is pressed 5 7 Adjustment of Primary Switch Door Sensing Switch and Monitor Switch Precaution For continued protection against radiation hazard replace parts in accordance with the wiring diagram and be sure to use the correct part number for the following switches Primary and secondary interlock switches and the interlock monitor switch replace all together Then follow the adjustment procedures below After repair and adjustment be sure to check the continuity of all interlock switches and the interlock monitor switch When mounting Primary switch and Interlock Monitor switch to Latch Body consult the figure No specific adjustment during installation of Primary switch and Monitor switch to the latch Switch body is necessary N 3 When mounting the Latch Body to the oven B ANN ody Latch assembly adjust the Latch Body by moving it so that the oven door will not have any play in it Check for play in the door by pulling the door Interlock assembly Make sure that the latch keys move Monitor smoothly after adjustment is completed Switch Completely tighten the screws holding the Latch hm Lever Door Body to the oven assembly 4 T 4 Reconnect to Monitor switch and check the toj Door Sensi continuity of the monitor circu
17. ective shields When reinstalling the chassis and its assemblies be sure to restore all protective devices including nonmetallic control knobs and compartment covers Make sure that there are no cabinet openings through which people particularly children might insert objects and contact dangerous voltages Examples Lamp hole ventilation slots Inform the manufacturer of any oven found to have emmission in excess of 5 mW cm2 Make repairs to bring the unit into compliance at no cost to owner and try to determine cause Instruct owner not to use oven until it has been brought into compliance SAMSUNG ELECTRONICS ITALY S P A VIA F LLI GRACCHI 48 20092 CINISELLO BALSAMO MILAN ITALY Service technicians should remove their watches while repairing an MWO Samsung Electronics 11 12 13 14 15 16 To avoid any possible radiation hazard replace parts in accordance with the wiring diagram Also use only the exact replacements for the following parts Primary and secondary interlock switches interlock monitor switch If the fuse is blown by the Interlock Monitor Switch Replace all of the following at the same time Primary and secondary switches as well as the Interlock Monitor Switch The correct adjustment of these switches is described elsewhere in this manual Make sure that the fuse has the correct rating for the particular model being repaired Design Alteration Warning Use exact re
18. it and all latch e wJ ae switches again by following the components test procedures 5 Confirm that the gap between the switch Door Open Door Closed housing and the switch actuator is no more than o switch ps 0 0 5mm when door is closed NG Monitor switch COM NO oo 0 Door Sensing S 0 5 2 Samsung Electronics Alignment and Adjustments 5 8 Output Power of Magnetron CAUTION MICROWAVE RADIATION PERSONNEL SHOULD NOT ALLOW EXPOSURE TO MICROWAVE RADIATION FROM MICROWAVE GENERATOR OR OTHER PARTS CONDUCTING M ICROW AVE ENERGY The output power of the magnetron can be measured by performing a water temperature rise test Equipment needed Two 1 liter cylindrical borosilicate glass vessel Outside diameter 190 mm One glass thermometer with mercury column NOTE Check line voltage under load Low voltage will lower the magnetron output Make all temperature and time tests with accurate equipment 1 Fill the one liter glass vessel with water 2 Stir water in glass vessel with thermometer and record glass vessel s temperature T1 10 1 C 3 After moving the water into another glass vessel place it in the center of the cooking tray Set the oven to high power and operate for 54 seconds exactly 2 seconds included as a holding time of magnetron oscillation 4 When heating is finished stir the water again with the thermometer and measure the temperature T2 Subtract T1 f
19. lay contacts and if it has continuity replace power relay also NOTE 2 When HVTransformer is replaced check diode and magnetron also Oven does not accept key input Program 1 Key input is not in Sequence 2 Open or loose connection of membrane key pad to Ass y PCB 3 Shorted or open membrane panel 4 Defective Ass y PCB Refer to operation procedure Replace PCB main Timer starts countdown but no microwave oscillation No heat while oven lamp and fan motor turn on 1 Off alignment of latch switches 2 Open or loose connection of high voltage circuit especially magnetron filament circuit NOTE Large contact resistance will bring lower magnetron filament voltage and cause magnetron to lower output and or intermittent oscillation 3 Defective high voltage components H V Transformer H V Capacitor H V Diode H V Fuse M agnetron 4 Open or loose wiring of power relay 5 Defective primary latch switch 6 Defective power relay or Ass y PCB Adjust door and latch switches Check high voltage component according to component test procedure and replace if it i defective Replace PCB main S Samsung Electronics Troubleshooting 6 1 Electrical Maltunction continved SYMPTOM CAUSE CORRECTIONS Oven lamp and fan motor turn on 1 Misadjustment or loose wiring of primary latch switch 2 Defective primary latch switch Adjust door and latch switches Oven c
20. placement parts only i e only those that are specified in the drawings and parts lists of this manual This is especially important for the Interlock switches described above Never alter or add to the mechanical or electrical design of the MWO Any design changes or additions will void the manufacturer s warranty 10 Always unplug the unit s AC power cord from the AC power source before attempting to remove or reinstall any component or assembly Never defeat any of the B voltage interlocks Do not apply AC power to the unit or any of its assemblies unless all solid state heat sinks are correctly installed Some semiconductor solid state devices are easily damaged by static electricity Such components are called Electrostatically Sensitive Devices ESDs Examples include integrated circuits and field effect transistors Immediately before handling any semiconductor components or assemblies drain the electrostatic charge from your body by touching a known earth ground Always connect a test instrument s ground lead to the instrument chassis ground before connecting the positive lead always remove the instrument s ground lead last 1 1 Pretaution 1 2 Special Servicing Precautions Continued 17 When checking the continuity of the witches or transformer always make sure that the power is OFF and one of the lead wires is disconnected 18 Components that are critical for safety are indicated in the circ
21. rom T2 This will give you the water temperature rise AT gi 6 The output power is obtained by the following formula 4 187 x 1000 x AT 52 3 Heating Time sec Output Power 52 3 4 187 Coefficient for Water 1000 Water cc AT Temperature Rise T2 T1 Output W 100 x AT 7 Normal temperature rise for this model is 9 C to 11 C at HIGH NOTE 1 Variations or errors in the test procedure will cause a variance in the temperature rise Additional power test should be made if temperature rise is marginal NOTE 2 Output power in watts is computed by multiplying the temperature rise step E by a factor of 91 times the of centigrade temperature 5 9 Microw ave Heat Distribution Heat Evenness The microwave heat distribution can be checked indirectly by measuring the water temperature rise at certain positions in the oven 1 Prepare five beakers made of Pyrex having 100 milliliters capacity each 2 Measure exactly 100milliliters off water load with a measuring cylinder and pour into each beaker 3 Measure the temperature of each water load Readings shall be taken to the first place of decimals 4 Put each beaker in place on the cooking tray as illustrated in figure below Start heating 5 After heating for 2 minutes measure the water temperature in each beaker 6 Microwave heat distribution rate can be calculated as follows Minimum Temperature Rise Heat Distribution X 100 Maximum Temperature
22. uit diagram by shading A or 19 Use replacement components that have the same ratings especially for flame resistance and dielectric strength specifications A replacement part that does not have the same safety characteristics as the original might create shock fire or other hazards 1 3 Special High Voltage Precautions 1 High Voltage Warning Do not attempt to measureany of the high voltages this includes the filament voltage of the magnetron High voltage is present during any cook cycle Before touching any components or wiring always unplug the oven and discharge the high voltage capacitor See Figure 1 1 2 The high voltage capacitor remains charged about 30 seconds after disconnection Short the negative terminal of the high voltage capacitor to to the oven chassis Use a screwdriver 3 High voltage is maintained within specified limits by close tolerance safety related components and adjustments If the high voltage exceeds the specified limits check each of the special components Fig 1 1 Discharging the High Voltage Capacitor 1 2 Samsung Electronics 2 Specifications 2 1 Table of Specifications TIMER 99 MINUTES 90 SECONDS POWER LEVEL ON TIME OFFTIME POWER SOURCE 230V 50Hz AC M757 POWER CONSUM PTION M ICROW AVE 1 300W 10 80W 4 sec 26 sec 0 OUTPUT POWER FROM 80 TO 800W 10 LEVEL POW ER 30 240W 10 sec 20 sec IEC
23. up the control circuit board from right side and remove the hooks holding the contol circuit board to the box assembly SCREWS Samsung Electronics 5 Alignment and Adjustments PRECAUTION 1 High voltage is present at the high voltage terminals during any cook cycle 2 It is neither necessary nor advisable to attempt measurement of the high voltage 3 Before touching any oven components or wiring always unplug the oven from its power source and discharge the high voltage capacitor 5 1 High Voltage Transformer 1 Remove connectors from the transformer terminals and check continuity 2 Normal resistance readings are as follows MODEL M757 Secondary Approx 1300 Filament Approx 0 Primary Approx 1 700 Room temperature 20 C 5 2 Low Voltage Transformer 1 The low voltage transformer is located on the control circuit board 2 Remove the low voltage transformer from the PCB Ass y and check continuity 3 Normal resistor reading is shown in the table 5 3 Magnetron m Continuity checks can indicate only an open filament or a shorted magnetron To diagnose an open filament or shorted magnetron Isolate the magnetron from the circuit by disconnecting its leads A continuity check across the magnetron filament terminals should indicate one ohm or less 4 A continuity check between each filament terminal and magnetron case should read open N C2 Samsung Electronics
24. urce Remove the 10A fuse in the fuse holder N When replacing the 10A fuse be sure to use an exact replacement part If new 10A fuse blows out again after replacement check the primary interlock switch door sensing switch and interlock monitor switch 4 When the above three switches operate properly check if any other part such as the control circuit board blower motor or high voltage transformer is defective 4 5 Replacement of Drive M otor m Take out the glass tray guide roller and coupler from cavity Turn the oven upside down to replace the drive motor Drive Motor Remove a screw securing the drive motor cover 2 3 4 Disconnect all the lead wires from the drive motor 5 cavity Remove screws securing the drive motor to the Remove the drive motor 7 When replacing the drive motor be sure to remount it in the correct position Connect all the leads to the drive motor 5 the deive motor cover to the base plate with a screw driver 10 Remount the coupler in the correct position Samsung Electronics 4 3 Disassembly and Reassembly 4 6 Replacement of Control Circuit Board 1 Be sure to disclyarge any static electricity from your body and avoid touching the Touch control clrcuitry 2 Disconnect the connectors from the control circuit board 3 Remove screws securing the control circuit bord 4 Lift
25. urvey meter checked for accuracy by its manufacturer 5 4 Samsung Electronics 6 Troubleshooting PRECAUTION 1 CHECK GROUNDING BEFORE CHECKING FOR TROUBLE 2 BE CAREFUL OF THE HIGH VOLTAGE CIRCUIT 3 DISCHARGE THE HIGH VOLTAGE CAPACITOR 4 WHEN CHECKING THE CONTINUITY OF THE SWITCHES OR TRANSFORMER DISCONNECT ONE LEAD WIRE FROM THESE PARTS AND THEN CHECK CONTINUITY WITHOUT THE POW SOURCE ON TO DO OTHERWISE M AY RESULT IN A FALSE READING OR DAMAGE TO YOUR METER 5 DO NOT TOUCH ANY PART OF THE CIRCUIT OR THE CONTROL CIRCUIT BOARD SINCE STATIC DISCHARGE M AY DAM AGE IT ALWAYS TOUCH GROUND WHILE WORKING ON IT TO DISCHARGE ANY STATIC CHARGE BUILT UP 6 1 Electrical Maltunction No display and no operation at all 3 Open low voltage transformer 4 Defective Ass y PCB SYMPTOM CAUSE CORRECTIONS Oven is dead 1 Open or loose lead wire harness Check fan motor when thermal cutout is defective Fuse is OK 2 Open thermal cutout M agnetron Check Ass y PCB when LVT is defective Fuse is blown No display and no operation at all 1 Shorted lead wire harness 2 Defective primary latch switch NOTE 1 3 Defective monitor switch NOTE 4 Shorted HVCapacitor 5 Shorted HVTransformer NOTE2 Check adjustment of primary interlock monitor door sensing switch NOTE 1 All of these switches must be rep refer to adjustment instructions aced at the same time Check continuity of power re
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