Read Panasonic NN-GD588S / NN-GT548M / NN-GT548MZPE / NN-GD588SZPE Service Manual Simplified online
5.4.2. NN-GT548M
SYMPTOM
STEP
CHECK
RESULT
CAUSE/CORRECTIONS
No display when oven is first plugged
in
in
1
Fuse pattern of D.P.C.
Normal
→Step2
Open
Replace D.P.C. or Fuse
Pattern
Pattern
2
Low voltage transforment (L.V.T.)
secondary voltage
secondary voltage
Abnormal 0V
L.V.T.
Normal
→Step3
3
IC1 pin47 voltage
Abnormal
Q10, ZD10
Normal=5V
IC1, CX320, Display
No key input
1
Membrane switch continuity
Abnormal
Membrane switch
Normal
IC1
No beep sound
1
IC1 pin 8 voltage
Abnormal
IC1
Normal=5V
BZ310, Q224
Power relay RY2 does not turn on
even though the program had been set
and the start button is tapped
even though the program had been set
and the start button is tapped
1
IC1 pin 41 voltage while operation
Abnormal
IC1
Normal=5V
→Step2
2
Collector of Q223 voltage
Abnormal
Q223
Normal 0.7V
RY2
No microwave oscillation at any power
1
IC1 pin 39 voltages while operation at high
power
power
Abnormal
IC1
Normal=5V
→Step2
2
Collector of Q220 voltage
Abnormal
Q220 and/or Q225
Normal 0.7V
→Step3
3
Short circuit between collector and emitter
of Q220
of Q220
Still not turn on
RY1, Q225
RY1 turns on
Q220
Dark or unclear display
1
Replace display and check operation
Normal
Display
Abnormal
IC1
Missing or lighting of unnecessary
segment
segment
1
Replace IC1 and check operation
Normal
IC1
Abnormal
Display
H95/H97/H98 appears in window and
oven stops operation.Program High
power for 1 minute and conduct
following test quickly, unless
H95/H97/H98 appears and oven stops
oven stops operation.Program High
power for 1 minute and conduct
following test quickly, unless
H95/H97/H98 appears and oven stops
1
Unplug CN702 (2 pin) connector and
measure voltage between terminals
measure voltage between terminals
Abnormal=0V
1. Latch Switch
2. D.P.C. /Power Relay
2. D.P.C. /Power Relay
Normal=220V
→Step2
2
Unplug CN701 (3 pin) connector and
measure pin1 voltage of CN3
measure pin1 voltage of CN3
Abnormal=0V
D.P.C.
Approx. AC 3V
Magnetron
5.5. SIMPLE WAY OF H.V. INVERTER/MAGNETRON TROUBLESHOOTING
Purpose:
Simple way (3/23 seconds rule) of identifying whether it’s Magnetron, Inverter or others.
Set-up:
The unit under question is connected through the Ammeter as shown below.
Procedure:
Follow the matrix table below to identify the problem source.
Note:
Do not replace both Inverter board and Magnetron simultaneously and automatically without going through this
procedure.
procedure.
Power will:
Ammeter reading is:
To do:
Remedy:
Shut off in 23 seconds
after “Start”.
after “Start”.
1. Between 0.5A and 1.0A.
Check and repair open magnetron circuit
CN703.
CN703.
Open magnetron wiring between Inverter
and magnetron terminal.
and magnetron terminal.
2. Between 1.0A and 2.0A.
Check continuity of D702 in Inverter PCB.
1. D702 shorted
Replace H.V.Inverter(F606YM300BP)
2. D702 is OK
Replace magnetron
Shut off in 3 seconds
after “Start”.
after “Start”.
1. Less than 0.5A
Check open circuit: Latch Switch, DPC,
Power Relay, CN701 and CN702.
Power Relay, CN701 and CN702.
Replace
defective
component(s),
or
correct switch, cables and connectors.
15
NN-GD588S / NN-GT548M
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