Panasonic NN-S262SF APH Service Manual page 37

1. Check grounding before checking for trouble.
2. Be careful of high voltage circuit.
3. Discharge high voltage capacitor.
4. When checking the continuity of the switches or the high voltage transformer,disconnect one lead wir
from these parts and then check continuity with the AC plug removed. To do otherwise may result in a
false reading or damage to your meter. / When disconnecting a plastic connector from a terminal, you
must hold the plastic connector instead of the lead wire and then disconnect it, otherwise lead wire m
be damaged or the connector cannot be removed.
5. Do not touch any parts of the circuitry on the digital programmer circuit, since static electric discharge
may damage this control panel. / Always touch yourself to ground while working on this panel to
discharge any static charge in your body.
6. 120V AC is present on the digital programmer circuit (Terminals of power relay's and primary circuit of
low voltage transformer). When troubleshooting, be cautious of possible electrical shock hazard.
First of all operate the microwave oven following the correct operating procedures in order to find the
exact cause of any trouble.
SYMPTOM
1. Oven is dead.
Fuse is OK.
No display and no operation
at all.
2. No display and no operation
at all. / Fuse is blown.
3. Oven does not accept key
input(Program)
4. Fan motor turn on when
oven is plugged in with door
closed.
CAUTION
CAUSE
1. Open or loose lead wire harness
Open thermal cutout (Magnetron)
2.
Open low voltage transformer
Defective DPC
3.
4.
1. Shorted lead wire harness
Defective primary latch switdh
2. (NOTE 1)
3. Defective short switch (NOTE 1)
4. Defective Inverter Power Supply (U)
Refer to component test procedure
NOTE 1:
All of these switches must be replaced at the same time.
Check continuity of power relay B (RY-1)'s contacts (between 1 and 2
and if it has continuity, replace power relay B (RY-1) also.
1. Key input is not insequence
Open or loose connection of
2. membrane key pad to DPC (Flat
cable)
3. Shorted or open membrane key
board
4. Defective DPC
3. Misadjustment or loose wiring of
secondary latch switch
4. Defective secondary latch switch
35
CORRECTIONS
Check fan motor when thermal
cutout is defective.
Check adjustment of primary,
secondary latch switch and sh
switch including door.
Refer to Inverter PCB
Troubleshooting.
Refer to operation procedure.
Refer to DPC troubleshooting.
Adjust door and latch switches