Troubleshooting - Samsung CE959G Service Manual

6. Troubleshooting

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 POWER SOURCE ON. TO DO OTHERWISE MAY 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 MAY DAMAGE IT.
ALWAYS TOUCH GROUND WHILE WORKING ON IT TO DISCHARGE ANY STATIC CHARGE BUILT UP.
Please don't mind if the oven works continuously after the cooking over.
Reason : This oven is designed to work without microwaves for 5 min to cool internal electric part after the
cooking over. (The "0 " indication flashes.)
Open the door or press any buttons except
6-1 Electrical Malfunction
SYMPTOM
Oven is dead.
Fuse is OK.
No display and no operation at all. 3. Open low voltage transformer
No display and no operation at all. 1. Shorted lead wire harness
Fuse is blown.
Timer starts countdown but no
microwave oscillation.
(No heat while oven lamp and
fan motor turn on.)
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PRECAUTION
1 min + button to stop the oven.
CAUSE
1. Open or loose lead wire harness
2. Open thermal cutout (Magnetron)
4. Defective Ass'y PCB
2. Defective primary latch switch (NOTE 1)
3. Defective monitor switch (NOTE1)
4. Shorted HVCapacitor
5. Shorted HVTransformer (NOTE2)
NOTE 1: All of these switches must be replaced at the same time.
(refer to adjustment instructions)
Check continuity of power relay contacts and if it has continuity, replace power
relay also.
NOTE 2: When HVTransformer is replaced, check diode and magnetron also.
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
Magnetron
4. Open or loose wiring of power relay
5. Defective primary latch switch
6. Defective power relay or Ass'y PCB
CORRECTIONS
Check fan motor when thermal cutout is defective.
Check Ass'y PCB when LVT is defective.
Check adjustment of primary, interlock monitor,
door sensing switch.
Adjust door and latch switches.
Check high voltage component according to
component test procedure and replace if it is
defective.
Replace PCB main.
6-1