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Daewoo KOC-970T1S, Service Manual, Page: 25 / 48

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Daewoo KOC-970T1S Service Manual Download Page 25

TROUBLE SHOOTING GUIDE

BUTTON KEYBOARD CHECK PROCEDURE

1. Type of button names

( key metrix and circuit diagram )

The tact switch keyboard consists of 10 keys which configurations are described above.

2. Key check procedure

To determine if the tact switch keyboard is defective or not, check the continuity of each 

button(key) contacts with a multimeter.

(1) AUTO COOK

button : between 4 and 10

(2) DEFROST

button : between 4 and 14

(3) TEMP           

button : between 8 and 12

(4) MICROWAVE     

button : between 6 and 14

(5) COMBI          

button : between 6 and 12

(6) GRILL           

button : between 2 and 10

(7) +10 SEC         

button : between 8 and 10

(8) +1 MIN          

button : between 6 and 10

(9) STOP/CLEAR     

button : between 2 and 12

(10) START          

button : between 4 and 12

(11) CLOCK         

button : between 8 and 14

(12) PIE             

button : between 2 and 14

Summary of Contents for KOC-970T1S

Page 1: ...Service Manual Microwave Oven Model KOC 970T1S KOC 970T2S KOC 980T10S KOC 980T20S DAEWOO ELECTRONICS CO LTD ...

Page 2: ... necessary 1 Interlock operation 2 Proper door closing 3 Seal and sealing surfaces arcing wear and other damage 4 Damage to or loosening of hinges and latches 5 Evidence of dropping or abuse c Before turning on power to the microwave oven for any service test or inspection within the microwave generating compartments check the magnetron wave guide or transmission line and cavity for proper alignme...

Page 3: ...y certified oven unit is found to servicing a microwave emission check should be performed prior to servicing the oven 1 inform the manufacturer importer or assembler 2 repair the unit at no cost to the owner 3 attempt to ascertain the cause of the excessive leakage 4 tell the owner of the unit not to use the unit until the oven has been brought into compliance 3 If the oven operates with the door...

Page 4: ...9 5 Kg 43 lbs TIMER 60 minutes FUNCTION SELECTIONS MICROWAVE GRILL CONVECTION COMBI POWER SELECTIONS 10 LEVELS CAVITY VOLUME 1 0 Cu Ft MODEL KOC980T10S KOC980T20S POWER SUPPLY 230V 50Hz 230V 50Hz POWER CONSUMPTION MICROWAVE 1450W 1450W GRILL 1200W 1200W CONVECTION 1550W 1550W AUTO COOK 1850W 1850W COMBINATION 2600W Simultaneous 1550W Sequential MICROWAVE ENERGY OUTPUT 1000W IEC705 1000W IEC705 MIC...

Page 5: ... EXTERNAL VIEW 1 OUTER DIMENSION KOC 970T KOC980T Fig 1 Front view Fig 2 Side view Fig 1 Front view Fig 2 Side view ...

Page 6: ... is designed so that light can pass through but not the microwave 4 Top heater Turns on when convection grill and combi cooking is selected 5 Oven lamp Automatically turns on during oven operating 6 Safety interlock system 7 Control panel 8 Turntable tray Rotates during cooking and ensure even distribution of Microwaves It can also be used as a cooking utensil 9 Oven front plate 10 Rotating base T...

Page 7: ...that light can pass through but not the microwave 4 Top heater Turns on when convection grill and combi cooking is selected 5 Oven lamp Automatically turns on during oven operating 6 Safety interlock system 7 Control panel 8 Turntable tray Rotates during cooking and ensure even distribution of Microwaves It can also be used as a cooking utensil 9 Oven front plate 10 Rotating base This fits over th...

Page 8: ...type which if damaged must be repaired with cable of same type Such a cable can be purchased from DAEWOO and must be installed by a Qualified Person 6 Examine the oven after unpacking for any damage such as A misaligned door broken door or a dent in cavity If any of the above are visible DO NOT INSTALL and notify dealer immediately 7 Do not operate the oven if it is colder than room temperature Th...

Page 9: ... or WEIGHT Used to set the cooking time time of day and weight input Dial Knob be ready to operate dial knob When blinking it informs you to Guide Lamp cooking time in 30 sec Used to program quickly Speedy Cook Button cooking cycle Used to start the selected Start Button Temp CONVECTION Combi COMBINATION increments Auto Cook Pie DEFROST DEFROST cooking mode cooking function Used to select desired ...

Page 10: ...ng repair work 2 Warning about the electric charge in the high voltage capacitor For about 30 seconds after the operation stopped and electric charge remains in the high voltage capacitor When replacing or checking parts short between oven chassis and the negative high terminal of the high voltage capacitor by using a properly insulated screwdriver to discharge 4 When the 15A fuse is blown out due...

Page 11: ...ward 2 To remove guide wind assembly 1 Remove two screws for earthing and for fixing to rear plate 2 Remove the noise filter from the guide wind 3 Pull the fan from the motor shaft 4 Remove two screws which secure the motor shaded pole 5 Remove the motor shaded pole 6 Reverse the above steps for reassembly ...

Page 12: ...te 2 Remove the H V transformer 3 Reverse the above steps for reassembly 4 To remove high voltage capacitor 1 Remove a screw which secure the grounding ring terminal of the H V diode and the capacitor holder 2 Remove the H V diode from the capacitor holder 3 Reverse the above steps for reassembly High voltage circuit wiring ...

Page 13: ...rse the above steps for reassembly Never install the magnetron without the metallic gasket plate which is packed with each magnetron to prevent microwave leakage Whenever repair work is carried out on magnetron check the microwave leakage It shall not exceed 4mW cm2 for a fully assembled oven with door normally closed CAUTION ...

Page 14: ...ART CODE PART NAME DESCRIPTION QTY REMARK B01 3511602400 DECORATOR C PANEL ABS 1 B02 3515501200 WINDOW DISPLAY PMMA IF 850 1 SMOG B03 3516715110 CONTROL PANEL ABS 1 B04 3516906000 BUTTON FUNCTION ABS 1 B05 3516905900 BUTTON FUNCTION ABS 1 KOR 816 B06 3516905800 BUTTON START ABS 1 KOR 816 B07 3516906100 BUTTON FUNCTION ABS 1 B08 PKBPMSQ200 PCB SUB AS KOC 970T 980T 1 B09 PKMPMSQ200 PCB MAIN AS KOC 9...

Page 15: ...e handle from the frame door REF NO PART CODE PART NAME DESCRIPTION QTY REMARK A01 3512203320 FRAME DOOR ABS 1 A02 3512601400 HANDLE DOOR ABS 1 A03 3517004020 BARRIER SCREEN O TEMPERED GLASS T3 2 1 A04 3515304700 SUPPORTER BARR S O NYLON 66 1 A05 3511708400 DOOR SEAL AS KOC 971C 1 A06 3513101100 HOOK POM 1 A07 3515101300 SPRING HOOK PW1 1 A08 3515203600 STOPPER HINGE T AS KOC 970T1S 1 A09 71214008...

Page 16: ...To reduce gap located on part D Loosen a screw on interlock switch assembly located top of oven body Following steps are same as step 3 Small gap may be acceptable if the microwave leakage does not exceed 1mW cm2 NOTE The door on a microwave oven is designed to act as an electronic seal preventing the leakage of microwave energy from the oven cavity during the cook cycle This function does not req...

Page 17: ... the motor syncro and supporter to bracket syncro motor 3 Remove two screws and under heater assembly in cavity 11 To remove grill heater assembly 1 Remove two screws which secure the cover insulator t to top plate 2 Remove the harness between heaters 3 Remove two screws for removing heater brackets 4 Remove heaters 5 Reverse the above steps for reassembly ...

Page 18: ...f cover insulator b 2 Remove four screws which secure the convection part assembly to the cavity rear plate 3 Remove a nut holding the convection fan and the pipe 4 Remove two screws which secure the bracket motor to cover insulator 5 Remove the cooling fan 6 Remove two screws which secure the motor shaded pole to the bracket motor 7 Reverse the above steps for reassembly ...

Page 19: ...sed the hook pushes the latch lever downward The latch lever presses the button of the interlock monitor switch to bring it under OFF condition and presses the button of the secondary interlock switch and door open monitor switch to bring it under ON condition 3 Adjustment steps 1 Loosen two mounting screws 2 Adjust interlock switch assembly position 3 Make sure that latch lever moves smoothly aft...

Page 20: ... and power cord before check parts listed below NOTE CONDITION CHECK RESULT CAUSE REMEDY Fuse blows Continuity COM NC COM NC No Continuity No Continuity Continuity Continuity 0 infinite Ω or Approx 150 210 normal Fuse again blows Replace NOTE 1 Replace NOTE 1 Replace NOTE 1 Replace Replace Check continuity of interlock monitor switch with door closed COM NC Check continuity of both primary and sec...

Page 21: ...t All these switches must be replaced at the same time please refer to 7 Interlock Mechanism and Adjust for adjustment instructions NOTE CONDITION CHECK RESULT CAUSE REMEDY Grill heater is not heated No Continuity Check continuity of primary interlock switch Check continuity of secondary interlock switch Check continuity of heater Check D C voltage being supplied to RELAY RY2 coil Malfunction of p...

Page 22: ...acts of RELAY RY3 or open relay coil REMEDY Replace Replace Replace Replace Replace Replace Replace Replace No microwave oscillation Check continuity of high voltage fuse Check continuity of high voltage rectifier in forward and backward direction with DC megger Check continuity of high voltage capacitor terminals with wires removed Connect megger leads to magnetron terminal and magnetron body Che...

Page 23: ...O M switch Check D C voltage being supplied to RELAY RY4 coil Malfunction of secondary interlock and D O M switch Defective touch control circuit Faulty contacts of RELAY RY4 or open relay coil CONDITION CHECK RESULT CAUSE REMEDY 1 Under heater is not heated 2 Convection fan and motor does not rotate No Continuity Adjust or replace Adjust or replace Replace Replace Malfunction of primary interlock...

Page 24: ...normally but no display shows 8 Display obviously jumps in time while counting down 9 Display counts down noticeably too fast while cooking 10 Display does not show the time of day when clear button is touched 11 Oven lamp and turntable motor do not stop although cooking is finished Check if the RELAY RY3 contacts close and if they are close replace touch control circuit CONDITION CHECK RESULT CAU...

Page 25: ...or not check the continuity of each button key contacts with a multimeter 1 AUTO COOK button between 4 and 10 2 DEFROST button between 4 and 14 3 TEMP button between 8 and 12 4 MICROWAVE button between 6 and 14 5 COMBI button between 6 and 12 6 GRILL button between 2 and 10 7 10 SEC button between 8 and 10 8 1 MIN button between 6 and 10 9 STOP CLEAR button between 2 and 12 10 START button between...

Page 26: ...er to the vessel the load is immediately placed on the center of the shelf which is in the lowest normal position 4 Microwave power is switched on 5 Heating time should be exactly A seconds Heating time is measured while the microwave generator is operating at full power The filament heat up time for magnetron is not included 6 The initial and final temperature of water is selected so that the max...

Page 27: ...s opened and when the door is closed 3 Monitor interlock switch 1 Disconnect the lead wire connecting the primary interlock switch and interlock monitor switch from primary interlock switch terminal 2 Connect the ohm meter leads between the lead wire connector disconnected as item1 and the power supply neutral plug pin 3 Read the value of resistance between the lead wire connector and the power su...

Page 28: ... on the door cabinet door seem door viewing screen the exhaust air vents and the suction air vents Measuring should be in a counter clockwise direction at a rate of 1 in sec If the leakage of the cabinet door seem is unknown move the probe more slowly When measuring near a corner of the door keep the probe perpendicular to the areas making sure the probe end at the base of the cone does not get cl...

Page 29: ...h the ohmmeter set on the highest resistance scale measure the resistance across the diode terminals Reverse the meter leads and again observe the resistance reading Meter with 6V 9V or higher voltage batteries should be used to check the front back resistance of the diode otherwise an infinite resistance may be read in both directions A normal diode s resistance will be infinite in one direction ...

Page 30: ... WIRING DIAGRAM ...

Page 31: ... SCHEMATIC DIAGRAM ...

Page 32: ... SCHEMATIC DIAGRAM ...

Page 33: ... SCHEMATIC DIAGRAM ...

Page 34: ... EXPLODED VIEWS AND PARTS LIST 1 KOC 970T EXPLODED VIEW ...

Page 35: ... U AS KOC 971COS 1 F14 7113400814 SCREW TAPPING T1 BIN 4 8 MFNI 2 F15 3510310400 BASE SBHG 1 T0 8 1 F16 3515202810 STOPPER HINGE U AS KOC 970T 1 F17 7S422X4081 SCREW SPECIAL TT2 TRS 4 8 SE MFZN 2 F18 3512100900 FOOT PP DASF 130 4 F19 4416W67820 CAPACITOR HV 2100VAC 1 1UF 1 F20 441X304112 HOLDER HV CAPACITOR SECC TO 8 1 F21 7S422X4081 SCREW SPECIAL TT2 TRS 4 8 SE MFZN 1 F22 4416V24000 DIODE HV SANK...

Page 36: ...KOC 970T2S 1 F48 4417B67600 FUSE 15A 250V KOC 970T1S 1 5F1CD1232M FUSE 12A 250V KOC 970T2S 1 F49 7S312X40A1 SCREW SPECIAL T1 TRS 4 10 SE MFZN 1 F50 35113A5Q5J CORD POWER AS 3 1 5 KOC 970T1S 1 35113A5QM5 CORD POWER AS 3 1 0 KOC 970T2S 1 F51 7S312X40A1 SCREW SPECIAL T1 TRS 4 10 SE MFZN 2 F52 7S427W40A1 SCREW SPECIAL TT2 HEX FG 4 10 SE MFZN 2 F53 3512505500 GUIDE AIR OUTLET SA1D 80 TO 5 1 F54 7S312X4...

Page 37: ... EXPLODED VIEWS AND PARTS LIST 2 KOC 980T EXPLODED VIEW ...

Page 38: ...10400 BASE SBHG TO 8 1 F16 3515202800 STOPPER HINGE U AS KOR 121MOA 1 F17 7S422X4081 SCREW SPECIAL TT2 TRS 4 8 SE MFZN 2 F18 3512101400 FOOT PP DASF 130 4 F19 4416W67820 CAPACITOR HV 2100VAC 1 1UF 1 F20 441X304112 HOLDER HV CAPACITOR SECC TO 8 1 F21 7S422X4081 SCREW SPECIAL TT2 TRS 4 8 SE MFZN 1 F22 4416V24000 DIODE HV SANKEN HVR 1X 32B D5 3 1 F23 3518112100 TRANS HV DY N90S0 97T1 1 F24 7S427W40A1...

Page 39: ...1011 SCREW TAPPING T1 TRS 4 10 MFZN 1 F55 3511404800 COVER INSULATOR T SECC TO 5 1 F56 7112401011 SCREW TAPPING T1 TRS 4 10 MFZN 1 F57 3510801000 CABINET PCM TO 5 1 F58 7112401011 SCREW TAPPING T1 TRS 4 10 MFZN 4 F59 3512513000 GUIDE TRAY AS KOC 971COS 1 F60 3517205200 TRAY METAL SPP TO 6 1 F61 3514800800 SENSOR TEMPERATURE PTM K312 D4 1 F62 7113400814 SCREW TAPPING T1 BIN 4 8 MFNI 1 F63 351870022...

Page 40: ... normal voltage 2 Voltage check Key check point 1 4 Micom Pin 5 Display Pin Check method KOC 970T 980T L V T DMR 101FS Terminal Voltage 1 2 230VAC 50Hz 4 5 13 0 VAC 6 7 35 0 VAC 8 10 3 0 VAC NO CHECK POINT REMARK 1 PIN 63 64 0 V 2 PIN 29 32 62 5 VDC 5 3 PIN 45 4 PIN 30 31 5 PIN 1 25 2 6 VAC Display filament voltage NO VOLTAGE REMARK KOC 970T 980T 1 5 VDC Replace R24 J3 Q10 2 12 VDC Replace D1 D6 J...

Page 41: ...n Grid 1 G1 21 24 GRILL PIE don t come on Grid 2 G2 17 17 COMBI TEMP COOK don t come on Grid 3 G3 14 18 WEIGHT DEFROST Kg don t come on Grid 4 G4 10 16 TIME DEFROST don t come on Grid 5 G5 4 7 13 Segment a doesn t come on from G1 to G5 Segment a 23 26 Segment b doesn t come on from G1 to G5 Segment b 22 25 Segment c doesn t come on from G1 to G5 Segment c 20 23 Segment d doesn t come on from G1 to...

Page 42: ... lamp does not turn on and turntable motor does not rotate but cook indicator in the display comes on CAUSE Relay 4 RY4 does not operate Check method c Situation When touching M W button oven lamp turns on and fan motor does not rotate but cook indicator in the display comes on CAUSE Relay 5 RY5 does not operate KOC 970T 980T STAGE POINT A POINT B RELAY3 ON 5 VDC GND RELAY3 OFF GND 12 VDC KOC 970T...

Page 43: ...ck method 6 Case of no heating of lower heater When touching TEMP COOK PIE button oven lamp turns on fan motor and turntable motor rotate and cook indicator in the display comes on CAUSE Relay 6 RY6 does not operate Check method STAGE POINT A POINT B RELAY5 ON 5 VDC GND RELAY5 OFF GND 12 VDC KOC 970T 980T STAGE POINT A POINT B RELAY2 ON 5 VDC GND RELAY2 OFF GND 12 VDC KOC 970T 980T STAGE POINT A P...

Page 44: ...heck method 8 Case of appearring Err6 on the display Check method KOC 970T 980T STAGE POINT A POINT B Door opened Open 5 VDC Door closed Closed GND KOC 970T 980T POINT WAVEFORM A B C Check the state ON OFF of the secondary interlock switch by resistance measurement NOTE If clock does not keep exact time you must check Diode D7 Transistor Q2 NOTE ...

Page 45: ... P C B CIRCUIT DIAGRAM 1 KOC 970T 980T ...

Page 46: ... RD AZ563J 1 R CABON FILM R3 4 14 15 1 6W 10K OHM J RD AZ103J 4 R CABON FILM R5 6 7 9 1 6W 4 7K OHM J RD AZ472J 4 R CABON FILM R2 8 1 6W 1K OHM J RD AZ102J 2 R CABON FILM R10 1 6W 330 OHM J RD AZ331J 1 R CABON FILM R16 1 6W 510 OHM J RD AZ511J 1 R CABON FILM R1 1 6W 100 OHM J RD AZ101J 1 R CABON FILM R23 1 4W 10K OHM F RN 4Z1002F 1 R CABON FILM R24 1 4W 120K OHM F RN 4Z1203F 1 DIODE SWITCHING D7 1...

Page 47: ...270Y 3 TRANSISTOR Q6 9 11 KRA102M TZRA102M 5 TRANSISTOR Q3 4 KRC102M TZRC102M 2 RELAY RY2 RY3 G5J 1 TP M DT 12 5SC0101112 2 RELAY RY4 6 G5B 1 12V 5SC0101110 3 R ARRAY RA1 RA3 8P 7 1 8 100KJ RA 88X104J 3 CONNECTOR FILM CN101 HLEM15R 1 4CW21RBD0 1 SW TACT SW101 112 KPT 1115AM 5S50101Z93 12 SW ROTARY EN101 SDB161VB17F 1 2 36 36PC PITCH5 5S10109002 1 NAME SYMBOL SPECIFCATION PART CODE Q TY P C B CIRCU...

Page 48: ...CS CO LTD 686 AHYEON DONG MAPO GU SEOUL KOREA C P O BOX 8003 SEOUL KOREA TELEX DWELEC K28177 8 CABLE DAEWOOELEC E mail G7F00E web dwe co kr FAX 02 360 8184 TEL 02 360 8178 8182 PRINTED DATE JUL 19988 S M NO C970T1S001 ...

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