Panasonic NN-GD368M / NN-GT348W / NN-GD368MZPE / NN-GD368MZTE / NN-GT348WZPE / NN-GT348MZPE Simplified Service Manual ▷ View online
5.3. Troubleshooting of inverter circuit (U) and magnetron
This oven is programmed with a self diagnostics failure code system which will help for troubleshooting. H95, H97, H98 and H99
are the provided failure codes to indicate magnetron and inverter circuit problem areas. This section explains failure codes of H95,
H97, H98 and H99. First, you must program the DPC into TEST MODE, press Timer/Clock pad twice
are the provided failure codes to indicate magnetron and inverter circuit problem areas. This section explains failure codes of H95,
H97, H98 and H99. First, you must program the DPC into TEST MODE, press Timer/Clock pad twice
→ Press Start pad once
→ press Micro Power pad once. Program unit for operation. H95, H97, H98, H99 appears in display window a short time after
[Start] button is pressed and there is no microwave oscillation.
[Start] button is pressed and there is no microwave oscillation.
Alternate way to troubleshoot oven with AC Ampere meter used
H95, H97, H98, H99 appears in display window a short time after [Start] pad is pressed and no microwave oscillation with AC
Ampere meter used for troubleshooting.
Ampere meter used for troubleshooting.
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NN-GD368M / NN-GT348W
5.4. Trouble related to Digital Programmer Circuit
5.4.1. NN-GD368M
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 pin23 voltage
Abnormal
Q11, ZD11
Normal=3.3V
IC1, CX320, Display
No key input
1
Membrane switch continuity
Abnormal
Membrane switch
Normal
IC1
No beep sound
1
IC1 pin 29 voltage
Abnormal
IC1
Normal=3.3V
BZ210, Q210
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 45 voltage while operation
Abnormal
IC1
Normal=3.3V
→Step2
2
Collector of Q223 voltage
Abnormal
Q223
Normal 0.7V
RY2
No microwave oscillation at any power
1
IC1 pin 47 voltages while operation at high
power
power
Abnormal
IC1
Normal=3.3V
→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
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NN-GD368M / NN-GT348W
5.4.2. NN-GT348W
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 pin23 voltage
Abnormal
Q11, ZD11
Normal=3.3V
IC1, CX320, Display
No key input
1
Membrane switch continuity
Abnormal
Membrane switch
Normal
IC1
No beep sound
1
IC1 pin 29 voltage
Abnormal
IC1
Normal=3.3V
BZ210, Q210
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 2 voltage while operation
Abnormal
IC1
Normal=3.3V
→Step2
2
Collector of Q225 voltage
Abnormal
Q225
Normal 0.7V
RY2
No microwave oscillation at any power
1
IC1 pin 1 voltages while operation at high
power
power
Abnormal
IC1
Normal=3.3V
→Step2
2
Collector of Q224 voltage
Abnormal
Q224 and/or Q231
Normal 0.7V
→Step3
3
Short circuit between collector and emitter
of Q224
of Q224
Still not turn on
RY1, Q231
RY1 turns on
Q224
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.
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NN-GD368M / NN-GT348W
5.6. How to check the semiconductors using an OHM meter
5.7. H.V. Inverter main parts list (F606YM300BP)
Ref. No.
Part No.
Part Name & Description
Pcs/Set
Remarks
Q701
A691EM300BP
IGBT
1
Q702
IGBT
1
C701
ECWF5184N300
FILM CAPACITOR
1
C702
ECQE2505T869
FILM CAPACITOR
1
C703
ECWF2395N632
FILM CAPACITOR
1
DB701
B0FBBS000001
RECTIFIER BRIDGE
1
L701
F5020M300GP
CHOKE COIL
1
R702
D0CM352JA002
SAND BAR RESISTOR
1
T701
A609AM300GP
TRANSFORMER
1
(INCLUDING D701, D702, C706, C707)
D701, D702
B0FBAZ000001
DIODE
2
C706
ECWH30562U03
FILM CAPACITOR
1
C707
ECWH30432U04
FILM CAPACITOR
1
16
NN-GD368M / NN-GT348W
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