Panasonic Inverter NN-CT776SBPQ Service Manual page 18

12.3 Troubleshooting (other problems)
Symptom
1. Microwave output is low.
Oven takes a long time to cook food.
2. Loud Buzzing noise can be heard.
3. Turntable motor does not rotate.
4. Oven stops operation during cooking
cycle.
5. Oven returns to "plug in" state 9
seconds after the start pad is
pressed in sensor cooking mode.
12.4 Troubleshooting the inverter by input voltage
Troubleshooting the Inverter circuit and magnetron
Microwave oven shuts down between 15 - 33 seconds.
If the microwave oven shuts down after a short period of time while operating in micropower mode, conduct the
following test.
The microwave oven must be set in self test mode to activate the self diagnostic failure code system.
Stop/Cancel
When oven is set in test mode, place water load (1Ltr) in the oven, set micropower to high and time for 1 minute,
press start.
H97, H98 appears in the display window for a short time after start key is pressed and there is no microwave oscil-
lation.
Cause
1. Decrease in power source volt-
age.
2. Open or loose wiring of magne-
tron filament circuit causing inter-
mittent oscillation.
3. Ageing of magnetron
1. Loose fan or fan motor
1. Open or loose wiring of turntable
motor.
2. Defective turntable motor
1. Open or loose wiring of primary
and secondary latch switch.
1. Open steam sensor circuit.
2. Defective steam sensor.
Delay/
S tand
20
Correction
Consult electrician.
Refer to output test procedures.
Change magnetron
Adjust door and latch switches.
Start
Micro Power