Panasonic NN-CT577SEPG Service Manual page 18

12.1 Troubleshooting (no operation)
Symptom
1. Oven is dead.
Fuse is OK
No display and no operation at all.
2. Oven does not accept key input
(Program).
3. Timer starts to countdown but no
microwave oscillation.
4. Oven does not operate & return to
plugged in mode as soon as Start
Pad is pressed
5. No display and no operation at all.
Fuse is Blown
12.2 Troubleshooting
Symptom
1. Oven stops in 3 seconds after
pressing start pad.
2. Oven stops in 23 seconds after
pressing start pad.
3. Oven stops in 1 minute after
pressing start pad.
(Convection/Grill convection
cooking)
Cause
1. Open or loose lead wire harness.
2. Open low voltage transformer.
3. Defective DPC AU or DPC DU
1. Key input is not in sequence.
2. Shorted push button on DPC AU
3. Defective DPC AU.
1. Maladjusted latch switches.
2. Open or loose connection of high
voltage circuit, including the mag-
netron filament circuit.
NOTE: A large contact resistance
lowers the magnetron filament volt-
age reducing the magnetron output
or causing intermittent operation.
3. Defective high voltage component
Inverter circuit or Magnetron.
4. Open or loose wiring of power
relay (RY1).
5. Defective primary latch switch.
6. Defective power relay RY1 or DPC
AU or DPC DU.
1. Defective DPC
1. Shorted lead wire harness.
2. Defective primary latch switch.
(NOTE 1)
3. Defective short switch.(NOTE 1)
4. Defective Inverter power supply.
(Refer to inverter circuit test pro-
cedure page)
NOTE 1: All of these switches must
be replaced at the same time. (Refer
to adjustment instructions page)
Check continuity of power relay RY1
Replace this relay if it is short cir-
cuit.
(Oven stops operation during cooking )
Cause
No input AC is supplied to
H.V.Inverter (U) CN702 terminals
H.V.Inverter (U) operates by the
control signalsfrom DPC but magne-
tron is not oscillating
Oven thermistor circuit is not
functioning
Correction
Refer to operation procedure.
Refer to DPC troubleshooting
Adjust door and latch switches.
Check high voltage components
according to the component test
procedure.
Check grounding connector on
esctcheon base.
Check adjustment of the Door, Pri-
mary, secondary and short latch
switches.
Correction
1. Latch Switch
2. Power relay RY1
3. Loose lead wire connector
CN701, CN702
1. Magnetron
2. Loose lead wire connector
CN703
1. Oven thermistor
2. Loose wiring
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