Daewoo KOT-1G1A User manual

Service Manual
Microwave Oven
Model: KOT-1G1A
S/M No. :
May. 2009
✔Caution
: In this Manual, some parts can be changed for improving,
their performance without notice in the parts list. So, if you
need the latest parts information, please refer to PPL(Parts
Price List) in Service Information Center (http://svc.dwe.co.kr).
MCO165UW/UB

1
PRECAUTIONS TO BE OBSERVED BEFORE AND
DURING SERVICING TO AVOID POSSIBLE
EXPOSURE TO EXCESSIVE MICROWAVE ENERGY
(a)Do not operate or allow the oven to be operated with the door open.
(b)Make the following safety checks on all ovens to be serviced before activating the magnetron or other micro-
wave source, and make repairs if 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
alignment, integrity, and connections.
(d)Any defective or misadjusted components in the interlock, monitor, door seal and microwave generation and
transmission systems shall be repaired, replaced, or adjusted by procedures described in this manual before
the oven is released to the owner.
(e)A microwave leakage check to verify compliance with the Federal performance standard should be
performed on each oven prior to release to the owner.
TABLE OF CONTENTS
PROPER USE AND SERVICE PRECAUTIONS.................................................................................................................2
SPECIFICATIONS...............................................................................................................................................................3
EXTERNAL VIEW................................................................................................................................................................4
INSTALLATION...................................................................................................................................................................4
OPERATIONS AND FUNCTIONS.......................................................................................................................................4
DISASSEMBLY AND ASSEMBLY......................................................................................................................................5
TROUBLE SHOOTING GUIDE .........................................................................................................................................28
MEASUREMENT AND TEST............................................................................................................................................31
WIRING DIAGRAM............................................................................................................................................................38
PRINTED CIRCUIT BOARD..............................................................................................................................................42
EXPLODED VIEW AND PARTS LIST...............................................................................................................................51

2
PROPER USE AND SERVICE PRECAUTIONS
CAUTION :
This Device is to be Serviced Only by Properly Qualified Service Personnel.
Consult the Service Manual for Proper Service Procedures to Assure Cotinued Safey Operation and for
Precautions to be Taken to Avoid Possible Exposure to Excessive Microwave Energy.
CAUTION :
Microwave Radiation
Personnel Should not Be Exposed to the Microwave Energy Which May Radiate from the Magnetron or Other
Microwave Generating device if it is Improperly Used or Connected. All Input and Output Microwave
Connections. Wave-Guides, Flanges and Gaskets Must be Secured. Never Operate the Device Without a
Microwave Energy Absorbing Load Attached. Never Look Into an Open waveguide or Antenna While the Device
is Energized.
1. FOR SAFE OPERATION
Damage that allows the microwave energy (that cooks or heats the food) to escape will result in poor cooking and may
cause serious bodily injury to the operator. IF ANY OF THE FOLLOWING CONDITIONS EXIST, OPERATOR MUST
NOT USE THE APPLIANCE.(Only a trained service personnel should make repairs.)
1) A broken door hinge.
2) A broken door viewing screen.
3) A broken front panel, oven cavity.
4) A loosened door lock.
5) A broken door lock.
The door gasket plate and oven cavity surface should be kept clean.
No grease, soil or spatter should be allowed to build up on these surfaces or inside the oven.
DO NOT ATTEMPT TO OPERATE THIS APPLIANCE WITH THE DOOR OPEN. The microwave oven has concealed
switches to make sure the power is turned off when the door is opened. Do not attempt to defeat them. DO NOT
ATTEMPT TO SERVICE THIS APPLIANCE UNTIL YOU HAVE READ THIS SERVICE MANUAL.
2. FOR SAFE SERVICE PROCEDURES
1) If the oven is operative prior to servicing, a microwave emission check should be performed prior to servicing the
oven.
2) If any certified oven unit is found to have excessive emission level 5mW/cm
2
, the service person should:
(a) inform the manufacturer, importer or assembler,
(b) repair the unit at no cost to the owner,
(c) attempt to ascertain the cause of the excessive leakage,
(d) 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 open, the service person should tell the user not to operate the oven and contact
the manufacturer and CDRH immediately.

3
Model KOT-1G1A
Power Supply 120V ~ 60 Hz, SINGLE PHASE WITH GROUNDING
Rated Current 14A
Power Consumption 1600W, Max.
Microwave Output Power (IEC 705) 1000W
Frequency 2450 MHz
Outside Dimensions (WxHxD) 760x427x373 mm ( 29.9" x 16.8" x 14.7" )
Cavity Dimensions (WxHxD) 514x248x347 mm ( 20.2" x 9.7" x 13.7" )
Net Weight 21.9Kg (48.3 lbs)
Timer Approx. 99 min 99sec
Power Selections 10 Levels
Cavity Volume 1.6 Cu. Ft.
Magnetron cooling Forced air
Microwave Distribution turntable
Rectification voltage doubler, half-wave.
Door Sealing Choke System
Safety Device Cavity Thermostat open : 212°F / 100°C, reset : 140°F / 60°C
Bottom Thermostat open : 203°F / 95°C, reset : 32°F / 0°C
Hood Thermostat open : 104 °F / 40°C, reset : 132.8°F / 56°C
Magnetron Thermostat open :320 °F/ 160 °C,reset :239 °F/ 115 °C
Line Fuse 20 A
Door Interlock Switches Primary Interlock Switch.
Secondary Interlock Switch.
Interlock Monitor.
Magnetron type RM228JFP (or 2M218JFP)
High Voltage Capacitor 0.98uf 2.1KV AC
High Voltage Diode 350 mA, 9.0 KV
Cook-top Lamp 125V, 30W
Cavity Lamp 125V, 30W
* SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE.
SPECIFICATIONS

4
EXTERNAL VIEW
; REFER TO THE INSTALLATION GUIDE
INSTALLATION
; REFER TO THE INSTALLATION GUIDE
OPERATIONS AND FUNCTIONS
; REFER TO THE USE AND CARE MANUAL

5
DISASSEMBLY AND ASSEMBLY
Caution to be observed when trouble shooting
Unlike many ther applicances, the microvave oven is high-voltage, high-current equipment.
It is completely safe during normal operation. However, carelessness is servicing the oven can result in an electronic shock
or possible danger from a short circuit. You are asked to observe the following precautions carefully.
1. Always remove the power plug from the outlet before servicing.
2. Use an insulated screwdriver and wear rubber gloves when servicing the high voltage side.
3. Discharge the high voltage capacitor before touching any oven components or wiring.
1) Check the grounding.
Do not operate on a two-wire extension cord.
It is imperative, therefore, make sure it is grounded properly before
beginning repair work.
2) Warning about the electric charge in the high voltage capacitor.
For about 30 seconds after the operation has stopped an 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 screwdrive to discharge.
4. When the 20A fuse is blown due to the operation for the monitor
switch; replace primary interlock switch, secondary interlock switch
and interlock monitor switch.
5. After repair or replacement of parts, make sure theat the screws are
properly tightened, and all electrical connections art tightened.
6. Do not operate without cabinet.
CAUTION :
Service personnel should remove their watches whenever working close to or replacing the magnetron.
CAUTION :
When servicing the appliance, take a care when touching or replacing high potential parts because of electrical
shock or exposing microwave. These parts are as follows-HV Transformer, Magnetron, HV Capacitor, HV
Diode.
SHORT

6
1. GENERAL
-REMOVING/REINSTALLING
-CABINET
CABINET REMOVAL
Refer to FIG. 1 for the following steps:
1. Remove the microwave oven from its mounting location and set it on a protected (padded) work surface.
2. Remove the two screws from the top of the microwave oven that secure the vent grille to the oven, and pull the top of
the vent grille out so the tabs are from their slots, and remove it.
3. Remove 1 screw from the vent motor cover.
4. Remove the remaining 13 screws from the top side and rear of the cabinet. Slide the cabinet back and unhook it from
the side tabs, then slide the power cord into the cabinet, and lift the cabinet off the oven.
Proceed to the section for the component you wish to service.
CABINET INSTALLATION
Refer to FIG. 1 for the following steps:
1. Position the cabinet over the top of the microwave oven and slide the power cord all the way through the top opening.
2. Slide the cabinet forward so that the tabs along the sides of the microwave fit into the corresponding slots in the
cabinet.
3. Loosely mount the screws to the top and sides of the cabinet. When all of the screws are installed, tighten them
securely.
4. Install the vent grille on the oven with the two long screws.
5. Install the oven in its mounting location.
WARNING :
Personal Injury Hazard
Disconnect from the electrical supply before servicing the unit. Failure to do so could result in electrical shock or
other personal injury.
CAUTION :
Personal Injury Hazard
Because of the weight and size of the microwave oven, two people are required to safely move and install it.
Failure to do so could result in personal injury.

7
FIG. 1

8
2.THE OPERATING CONTROL SYSTEMS
-REPLACING THE CONTROL CIRCUIT BOARD
1. Remove the two screws from the top of the microwave oven for the vent grille and remove the grille(See FIG. 1).
Refer to FIG. 2, FIG. 2-1 for the following steps:
2. Remove the screw on the front of the microwave oven for wire protector and remove the wire protector.
3. From the top and back of the control panel, lift the top locking tab and pull the top of the panel out slightly, then lift the
bottom tabs of the panel out of the slots and pull it forward.
WARNING :
This Device is to be Serviced Only by Properly Qualified Service Personnel.
Consult the Service Manual for Proper Service Procedures to Assure Continued Safety Operation and for
Precautions to be Taken to Avoid Possible Exposure to Excessive Microwave Energy.
FIG. 2

9
4. Unplug the following connectors from the control circuit board:
a) 2-Pin connector at CN1.
b) 2-Pin connector on relay RY1.
c) 7-Pin connector at CN3.
d) Lift the end of the locking arm on the ribbon cable at CN2, then lift the ribbon cable out of the socket.
5. Remove 4 screws from the control circuit board and lift the board off the mounting bracket.
6. Clean the surface of the new display and the inside of the control panel window with a soft, damp cloth to remove any
dirt, smudges, or lint.
7. Mount the new control circuit board to the mounting bracket with 4 screws.
8. Plug the following connectors over their control circuit board plugs so that they lock into place:
a) 2-Pin connector at CN1.
b) 2-Pin connectors on relay RY1.
c) 7-Pin connector at CN3.
d) Insert the end of the ribbon cable into the narrow slot of connector CN2 as far as it will go(See DETAIL CN2).
Lower the locking arm so that the two small tabs fit into the cutouts of the ribbon cable, then press down so that it
locks into place.
9. Mount the control panel to the oven and secure it with its mounting screw.
10. Mount the vent grille to the microwave oven and check out the operation.
FIG. 2-1