Daewoo KOC-972T0S Service Manual Download Page 47

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PRINTED WIRING BOARD

4. Case of no microwave oscillation

(1) Situation : When touching M/W button, oven lamp turns on, fan motor and turntable motor rotate and cook

indicator in the display comes on.

•

CAUSE : Relay 1 (RY1) does not operate.

•

Check method

(2) Situation : When touching M/W button, oven 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.(KOC-972T/982T)

Relay 3 (RY3) does not operate.(KOC-983T/984T/985T)

•

Check method

(3) 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-972T/982T)

Relay 4 (RY4) does not operate.(KOC-983T/984T/985T)

KOC-972T/982T

KOC-983T/984T/985T

STAGE

POIN T A

POINT B

R ELAY O N

+ 5 V D C

G N D

R EL AY O F F

G N D

+1 2 V D C

KO C-972T/982T

KO C-983T/984T/985T

STAGE

POIN T A

POINT B

R ELAY O N

+ 5 V D C

G N D

R EL AY O F F

G N D

+1 2 V D C

KOC-972T/982T

KOC-983T/984T/985T

Summary of Contents for KOC-972T0S

Page 1: ...Service Manual Microwave Oven Model KOC 972T0S KOC 972T2S KOC 982T1S KOC 982T2S KOC 983T1S KOC 983T2S KOC 984T1S KOC 984T2S KOC 985T1S KOC 985T2S DAEWOO ELECTRONICS CO LTD S M No C972T0S002 ...

Page 2: ...e repairs as 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 pr...

Page 3: ...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 o...

Page 4: ...MER 60 minutes FUNCTION SELECTIONS MICROWAVE GRILL CONVECTION COMBI POW ER SELECTIONS 10 LEVELS CAVITY VOLUME 1 0 Cu Ft MODEL KOC 982T 983T 984T 985T1S KOC 982T 983T 984T 985T2S POW ER SUPPLY 230V 50Hz 230V 50Hz POW ER CONSUMPTION MICROWAVE 1450W 1450W GRILL 1200W 1200W CONVECTION 1550W 1550W PROGRAM COOK 1850W 1850W COMBINATION 2600W Simultaneous 1550W Sequential MICROWAVE ENERGY OUTPUT 1000W IEC...

Page 5: ... EXTERNAL VIEW 1 OUTER DIMENSION KOC 972T KOC 982T 983T 984T 985T ...

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: ... 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 the sh...

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: ...ECTION Used to select the variable Microwave Power Level microwave power level If cooking mode cooking mode cooking mode operating in COMBI When blinking the oven is When blinking the oven is operating in GRILL When blinking the oven is operating in MICROWAVE cooking mode cooking mode cooking function M W MICROWAVE Used to select desired Function Buttons pads scrolled up automatically 1 3 sec numb...

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: ...e 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: ...ESCRIPTION QTY REMARK B01 3516715120 CONTROL PANEL ABS XR 401 1 B02 3515501210 W INDOW DISPLAY PMMA IF 850 1 B03 3516905100 BUTTON FUNCTION A ABS XR 401 1 B04 3516906200 BUTTON FUNCTION B ABS XR 401 1 B05 3513404600 KNOB VOLUME ABS XR 401 1 B06 3516906300 BUTTON FUNCTION C ABS XR 401 2 B07 PKBPMSP500 PCB SUB AS KOC 972T KOC 982T 1 B08 7621301011 SCREW TAPPING T2S PAN 3x10 PW MFZN 6 B09 PKMPMSQ300 ...

Page 15: ...buttons 4 Remove the knob volume REF NO PART CODE PART NAME DESCRIPTION QTY REMARK B01 3516719220 CONTROL PANEL ABS XR 401 1 B02 3511603120 DECORATOR C PANEL PET T0 2 1 B03 3513405200 KNOB VOLUME ABS XR 401 1 B04 3516906300 BUTTON FUNCTION ABS XR 401 1 B05 PKBPMSYB00 PCB SUB AS KOC 984T 1 B06 7621301011 SCREW TAPPING T2S PAN 3X10 PW MFZN 6 B07 PKMPMSYB00 PCB MAIN AS KOC 983T1S KOC 983T2S 1 B08 712...

Page 16: ...TROL PANEL ABS XR 401 1 B02 3511602900 DECORATOR C P T STS304 T0 6 H L 1 B03 3511603000 DECORATOR C P U STS304 T0 6 H L 1 B04 3511603110 DECORATOR C PANEL PMMA IF 850 1 SMOG B05 3511602800 DECORATOR RING ABS XR 401 1 COATING B06 3513404620 KNOB VOLUME ABS XR 401 1 COATING B07 3516905120 BUTTON FUNCTION ABS XR 401 1 COATING B08 3516907200 BUTTON FUNCTION ABS XR 401 1 COATING B09 3516906320 BUTTON F...

Page 17: ...RT NAME DESCRIPTION QTY REMARK B01 3516719210 CONTROL PANEL ABS XR 401 1 B02 3511603100 DECORATOR C PANEL STS304 T0 6 H L 1 B03 3515501400 W INDOW DISPLAY PMMA IF 850 1 SMOG B04 3513404620 KNOB VOLUME ABS XR 401 1 COATING B05 3516905120 BUTTON FUNCTION ABS XR 401 1 COATING B06 3516907200 BUTTON FUNCTION ABS XR 401 1 COATING B07 3516906320 BUTTON FUNCTION ABS XR 401 2 COATING B08 PKBPMSYB00 PCB SUB...

Page 18: ...ing 6 Remove the handle from the frame door REF NO PART CODE PART NAME DESCRIPTION QTY REMARK A01 3511708400 DOOR SEAL AS KOC 971C0S 1 A02 3513101100 HOOK POM 1 A03 3515101300 SPRING HOOK PW 1 1 A04 3517004030 BARRIER SCREEN O TEMPERED GLASS T3 2 1 A05 3512203360 FRAME DOOR ABS XR 401 1 A06 3512601430 HANDLE DOOR ABS XR 401 1 A07 3515203600 STOPPER HINGE T AS KOC 970T1S 1 A08 3512300800 GASKET DOO...

Page 19: ...CODE PART NAME DESCRIPTION QTY REMARK A01 3511708400 DOOR SEAL AS KOC 971C0S 1 A02 3513101100 HOOK POM 1 A03 3515101300 SPRING HOOK PW 1 1 A04 3517004030 BARRIER SCREEN O TEMPERED GLASS T3 2 1 A05 3512204010 FRAME DOOR ABS XR 401 1 A06 3512300800 GASKET DOOR PBT 1 A07 3515203600 STOPPER HINGE T AS KOC 970T1S 1 DISASSEMBLY AND ASSEMBLY ...

Page 20: ...300 SPRING HOOK PW1 1 A04 3517004080 BARRIER SCREEN O TEMPERED GLASS T3 2 1 MIRROR A05 3512204000 FRAME DOOR ABS XR 401 1 A06 3511603200 DECORATOR DOOR T STS304 T0 6 H L 1 A07 3511603300 DECORATOR DOOR U STS304 T0 6 H L 1 A08 3515203600 STOPPER HINGE T AS KOC 970T 1 A09 3512602400 HANDLE DOOR T AS ABS XR 401 WOOD GRAIN 1 KOC 984T 3512602410 HANDLE DOOR T AS ABS XR 401 SILVER COAT 1 KOC 985T A10 35...

Page 21: ...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 22: ...or 3 Remove two screws and under heater assembly in cavity 11 To remove grill heater assembly KOC 972T 1 Remove a nut which secure the heater holder inserting the wire of grill heater to side plate 2 Remove two nuts and a screw which secure the heater bracket to grill heater 3 Remove two heater brackets 4 Pull the heater holder inward and then remove the grill heater 5 Reverse the above steps for ...

Page 23: ...y KOC 982T KOC 983T KOC 984T KOC 985T only 1 Remove cover b and cover insulator b protecting convection part assembly release two lances of 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 Re...

Page 24: ...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 25: ...als 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 ...

Page 26: ...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 27: ...acts of RELAY RY1 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 28: ... M switch Check D C voltage being supplied to RELAY RY3 coil Malfunction of secondary interlock and D O M switch Defective touch control circuit Faulty contacts of RELAY RY3 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 29: ...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 Before following the parti...

Page 30: ...ctive or not check the continuity of each button key contacts with a multimeter 1 PROGRAM COOK button between 4 and 15 2 TIME DEFROST button between 8 and 14 3 WEIGHT DEFROST button between 8 and 14 4 COMBI button between 6 and 15 5 GRILL button between 8 and 12 6 M W button between 8 and 15 7 PIE button between 8 and 10 8 SPEEDY COOK button between 6 and 10 9 TEMP button between 6 and 14 10 START...

Page 31: ...ater 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 m...

Page 32: ...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 33: ... 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 34: ...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 35: ... WIRING DIAGRAM ...

Page 36: ... SCHEMATIC DIAGRAM ...

Page 37: ... SCHEMATIC DIAGRAM ...

Page 38: ... SCHEMATIC DIAGRAM ...

Page 39: ... EXPLODED VIEWS AND PARTS LIST 1 KOC 972T EXPLODED VIEW ...

Page 40: ...00814 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 4416W 67820 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 35...

Page 41: ...O7 KOC 972T2S 1 F48 4417B67600 FUSE 15A 250V 1 5F1CD1232M FUSE 12A 250V 1 F49 7S312X40A1 SCREW SPECIAL T1 TRS 4 10 SE MFZN 1 F50 35113A5Q5J CORD POW ER AS 3 1 5 KOC 972T0S 1 35113A5QM5 CORD POW ER AS 3 1 0 KOC 972T2S 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 7S312X40A1 SCREW SPECIAL...

Page 42: ... EXPLODED VIEWS AND PARTS LIST 2 KOC 982T 983T 984T 985T EXPLODED VIEW ...

Page 43: ...300 COUPLER CERAMIC 1 F09 3966510200 MOTOR SYNCRO 230V 25W GM 16 24FD24 1 F10 7121400811 SCREW TAPPING T2S PAN 4 8 MFZN 2 F11 3510604000 BRACKET MOTOR SYNCRO SECC TO 8 1 F12 7113400814 SCREW TAPPING T1 BIN 4 8 MFNI 1 F13 3512802100 HEATER U AS KOC 971COS 1 F14 7113400814 SCREW TAPPING T1 BIN 4 8 MFNI 2 F15 3510310400 BASE SBHG TO 8 1 F16 3515202800 STOPPER HINGE U AS KOR 121MOA 1 F17 7S422X4081 SC...

Page 44: ...1 SCREW TAPPING T1 TRS 4 10 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 7112401011 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 ...

Page 45: ... L V T DMR 101FS L V T DMR 984FS Terminal Voltage Terminal Voltage 1 2 230VAC 50Hz 1 3 230VAC 50Hz 4 5 13 0 VAC 6 7 10 5 VAC 6 7 35 0 VAC 7 8 10 5 VAC 8 10 3 0 VAC 9 10 2 6 VAC NO CHECK POINT REMARK 1 PIN 63 64 5 VDC 5 2 PIN 29 32 62 0 V 3 PIN 28 5 VDC 4 PIN 45 5 PIN 30 31 6 PIN 1 25 2 6 VAC Display filament voltage NO VOLTAGE REMARK KOC 982T KOC 983T 984T 985T 1 5 VDC Replace Q3 ZD2 R25 C12 Repla...

Page 46: ...t come on Grid 1 G1 4 7 13 Grid 2 doesn t come on Grid 2 G2 10 16 Grid 3 doesn t come on Grid 3 G3 14 18 Grid 4 doesn t come on Grid 4 G4 17 17 Grid 5 doesn t come on Grid 5 G5 21 24 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 G5 Segment d...

Page 47: ...play comes on CAUSE Relay 4 RY4 does not operate KOC 972T 982T Relay 3 RY3 does not operate KOC 983T 984T 985T Check method 3 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 972T 982T Relay 4 RY4 does not operate KOC 983T 984T 985T KOC 972T 982T KOC 983T 984T 985T STAGE POINT A POI...

Page 48: ...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 KOC 972T 982T Relay 5 RY5 does not operate KOC 983T 984T 985T Check method STAGE POINT A POINT B RELAY ON 5 VDC GND RELAY OFF GND 12 VDC KOC 972T 982T KOC 983T 984T 985T STAGE POINT A POINT B RELAY ON 5 VDC GND RELAY OFF GND 12 VDC...

Page 49: ...display Check method KOC 972T 982T KOC 983T 984T 985T STAGE POINT A POINT B Door opened Open 5 VDC Door closed Closed GND KOC 972T 982T KOC 983T 984T 985T POINT WAVEFORM A B C If clock does not keep exact time you must check Diode D1 Transistor Q2 KOC 972T 982T Diode D1 Transistor Q1 KOC 984T 985T NOTE Check the state ON OFF of the secondary interlock switch by resistance measurement NOTE ...

Page 50: ...49 P C B CIRCUIT DIAGRAM 1 KOC 972T 982T ...

Page 51: ...68 OHMJ 982T RD 4Z680J 1 DIODE SWITCHING D1 1N4148M DZN4148M 1 DIODE ZENER D2 8 10 11 1N4002A DZN4002A 9 DIODE ZENER ZD1 MTZ 3 9B DZUZ3R9BSB 1 DIODE ZENER ZD2 UZ 5 6B DZUZ5R6BSB 1 DIODE ZENER ZD3 MTZ 4 7B DZUZ4R7BSB 1 DIODE ZENER ZD4 MTZ 24B DZUZ24BSB 1 C ELECTRO EC1 RS 50V 10UF CEXE1H100A 1 C ELECTRO EC3 RSS 25V 2200UF CEXF1V102V 1 C ELECTRO EC4 RSS 50V 470UF CEXF1H471V 1 C ARRAY CA1 8P 7 50V 100...

Page 52: ... P C B CIRCUIT DIAGRAM KOC 983T 984T 985T ...

Page 53: ...CERA AXIAL C1 C8 C15 H1KF 50V 0 1UF Z CCZF1H104Z 9 C CERA AXIAL C6 C7 H1KF 50V 0 047UF Z CCZF1H473Z 2 C CERA AXIAL C2 C5 H1KF 50V 1000PF K CCZF1H102Z 4 C ARRAY CA1 8P 7 50V 1000 PF CN7XB 102M 1 DIODE SWITCHING D1 1N4148M DZN4148M 1 DIODE SWITCHING D2 D10 1N4004A DZN4004A 9 R CARBON FILM R1 R4 R12 R14 R24 1 6W 100K OHM J RD AZ104J 7 R CARBON FILM R5 R9 R11 R20 R27 1 6W 1K OHM J RD AZ102J 5 R CARBON...

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