NN-C781JF - Panasonic Home Appliance Service Manual (repair manual). Page 22

1. DO NOT RE-ADJUST PRESET VOLUME on the H.V.Inverter (U). It is very dangerous to repair or adjust without sufficient

test equipment because this circuit handles very large current with high voltage. Off alignment of inverter board operation
will be dangerous.

2. Ensure proper grounding before checking for trouble.
3. Be careful of the high voltage circuitry, taking necessary precautions when troubleshooting.
4. Discharge high voltage remains in the H.V.Inverter (U).
5. When checking the continuity of the switches or the H.V.Inverter, disconnect one lead wire 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 may be open or the connector cannot be removed.

6. 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.

7. 120V/220V/230V/240V AC is present on the digital programmer circuit (Terminals of power relay’s and primary circuit

of Digital Programmer Circuit). When troubleshooting, be cautious of possible electrical shock hazard.

1.

Oven stops in 3 seconds after pressing start pad

Oven stops in 23 seconds after pressing start pad

Oven stops in 10 seconds after pressing start pad

(Auto sensor cooking)

Oven stops in 60 seconds after pressing start pad

2.

No display and no operation at all.

Fuse is blown.

1. Latch Switch

2. Power relay RY-1

3. Loose lead wire connector CN701, CN702

1. Magnetron

2. Loose lead wire connector CN703

1. Steam sensor

2.DPC

3. Loose wiring connector CN2

1. Oven temp. sensor

2. Loose wiring CN5

1. Allign door, Door Latch Switches

2. Loose wiring connectors

Before troubleshooting, operate the microwave oven following the correct operating procedures in the instruction manual in order to find the exact

cause of any trouble, since operator error may be mistaken for the oven’s malfunction.

No 120/220/230/240V AC is supplied to

H.V.Inverter (U) CN702 terminals

H.V.Inverter (U) operates by the control signals

from DPC but magnetron is not oscillating

Steam sensor circuit is not functions

Oven temperature sensor circuit is not functions

Most probably loose connection of connectors or

door latch mechanizm is not adjusted properly

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