Troubleshooting Of Inverter Circuit (U) And Magnetron New H - Panasonic NN­GS595A Service Manual

10/24/2016
2. No display and no operation at
SYMPTOM
all.
Fuse is blown.
Oven does not accept key input
3.
(Program)
Fan motor turns on when oven is
4.
plugged in with door closed.
5.
Timer starts count down but no
microwave oscillation.
(No heat while oven lamp and
fan motor turn on)
Oven can program but timer
6.
does not start countdown.
Microwave output is low. Oven
7.
takes longer time to cook food.
Fan motor turns on and turntable
8.
rotates when door is opened.
Oven does not operate and
9. return to plugged in mode as
soon as start pad is pressed.
Loud buzzing noise can be
10.
heard.
11. Heater does not turn on.
Oven stops operation during
12.
cooking.
7.3 Troubleshooting of inverter circuit (U) and
magnetron NEW H.V.
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2. Defective primary latch switch (NOTE 1) CAUSE
3. Defective short switch (NOTE 1)
4. Defective Inverter Power Supply (U)
NOTE 1:
All of these switches must be replaced at the same time.
Check continuity of power relay B (RY­1)ʼs contacts (between 1 and 2) and if it has
continuity, replace power relay B (RY­1) also.
1. Key input is not in proper sequence
Open or loose connection of membrane key pad to
2.
DPC (Flat cable)
3. Shorted or open membrane key board
4. Defective DPC
Misadjustment or loose wiring of secondary latch
1.
switch
2. Defective secondary latch switch
1. Off­alignment of latch switches
Open or loose connection of high voltage circuit
especially magnetron filament circuit
NOTE:
2.
Large contact resistance will cause lower
magnetron filament voltage and cause magnetron
to have lower output and/or be intermittent.
Defective high voltage component H.V. Inverter
3.
Power Supply (u) Magnetron
4. Open or loose wiring of power relay B (RY­1)
5. Defective primary latch switch
6. Defective DPC or power relay B (RY­1)
1. Open or loose wiring of secondary latch switch
2. Off­alignment of secondary latch switch
3. Defective secondary latch switch
1. Decrease in power source voltage
Open or loose wiring of magnetron filament circuit.
2.
(Intermittent oscillation)
3. Aging change of magnetron
1. Shorted primary latch switch
1. Defective DPC
1. Loose fan and fan motor
1. Open or loose wiring of heater
2. Defective heater
3. Defective power relay
4. Defective DPC
Open or loose wiring of primary and secondary
1.
latch switch
2. Operation of thermal cutout
Check adjustment of primary,
CORRECTIONS
secondary latch switch and short
switch including door.
Refer to operation procedure.
Refer to DPC troubleshooting.
Adjust door and latch switches.
Adjust door and latch switches.
Check high voltage component
according to component test
procedure and replace if it is
defective.
Check high voltage component
according to component test
procedure and replace if it is
defective.
Refer to DPC troubleshooting
Consult electrician
Check grounding connector on
escutcheon base.
Adjust door and latch switches.
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