Troubleshooting Guide; Troubleshooting) Oven Stops Operation During Cooking - Panasonic NN-ST452W Service Manual

NN-SD452W / NN-ST462M / NN-ST452W

7 TROUBLESHOOTING GUIDE

1. DO NOT RE-ADJUST PRESET CONTROL on the H.V.Inverter (U). It is very dangerous to repair or adjust without proper test equipment
because this circuit generates very large current and high voltage. Operating a misaligned inverter circuit is dangerous.
2. Ensure proper grounding before troubleshooting.
3. Be careful of the high voltage circuitry, taking necessary precautions when troubleshooting.
4. Discharge high voltage remaining 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. Doing 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 damaged 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 ground while working on this panel to discharge any static charge in your body.
7. 230-240V 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.
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.
7.1.

(Troubleshooting) Oven stops operation during cooking

SYMPTOM
1. Oven stops in 3 seconds after
. pressing [Start] button.
Oven stops in 23 seconds after
pressing [Start] button.
Oven stops in 10 seconds after
pressing [Start] button.
(Auto sensor cooking)
2. No display and no operation at all.
Fuse is blown.
DANGER: HIGH VOLTAGES
CAUSE
No input 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 functioning
Most probably loose connection of connectors, or
door latch mechanism is not adjusted properly
1. Latch Switch
2. Power relay RY1
3. Loose lead wire connector CN701, CN702
4. H.V. Inverter (U)
1. Magnetron
2. Loose lead wire connector CN703
3. H.V. Inverter (U)
1. Steam sensor
2. DPC
3. Open or loose wiring of sensor terminal from
connector CN2 on DPC
1. Align door, Door Latch Switches
2. Loose wiring connectors
18
CORRECTIONS