Trouble Related To Digital Programmer Circuit; Simple Way Of H.v. Inverter/Magnetron Troubleshooting - Panasonic NN-GS597M Service Manual

9.4.

Trouble related to Digital Programmer Circuit

SYMPTOM
No display when oven is first plugged
in
No key input
No beep sound
Power relay (RY7) does not turn on
even though the program had been set
and the [Start] button is tapped
No microwave oscillation at any power
Dark or unclear display
Missing or lighting of unnecessary
segment
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
9.5.

Simple way of H.V. Inverter/magnetron troubleshooting

Purpose:
Simple way (3/37 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.
Power will:
Shut off in 37 seconds 1. Between 0.5A and 1.0A.
after "Start".
2. Between 1.0A and 2.0A.
Shut off in 3 seconds 1. Less than 0.5A
after "Start"
STEP
1 Fuse pattern of D.P.C.
2 Low voltage transforment (L.V.T.)
secondary voltage
3 IC10 pin5 voltage
1 Membrane switch continuity
1 IC1 pin 38 voltage
1 IC1 pin 37 voltage while operation
2 Short circuit IC220 pin10 to "0V"
1 IC1 pin 34 voltages while operation at high
power
2 Short circuit IC220 pin13 to "0V"
1 Replace display and check operation
1 Replace IC1 and check operation
1 Unplug CN702 (2 pin) connector and
measure voltage between terminals
2 Unplug CN701 (3 pin) connector and
measure pin3 voltage
Ammeter reading is:
Check and repair open magnetron circuit Open magnetron wiring between Inverter
Check continuity of D702 in Inverter PCB.
1. D702 shorted
2. D702 is OK
Check open circuit: Latch Switch, DPC,
Power Relay and CN701
CHECK
Normal
Open
Abnormal 0V
Normal
Abnormal
Normal=5V
Abnormal
Normal
Abnormal
Normal=5V
Abnormal
Normal=5V
Still not turn on
RY7 turns on
Abnormal
Normal=5V
Still not turn on
RY3 turns on
Normal
Abnormal
Normal
Abnormal
Abnormal=0V
Normal=220~240V →Step2
Abnormal=0V
Approx. AC 3V
To do:
27
RESULT CAUSE/CORRECTIONS
→Step2
Replace D.P.C. or Fuse
Pattern
L.V.T.
→Step3
IC10
IC1, CX320, Display
Membrane switch
IC1
IC1
BZ210, Q210
IC1
→Step2
RY7
IC220
IC1
→Step2
RY3
IC220
Display
IC1
IC1
Display
1. Latch Switch
2. D.P.C. /Power Relay
D.P.C.
Magnetron
Remedy:
and magnetron terminal.
Replace H.V.Inverter
(F606YM300BP)
Replace magnetron
Replace defective component(s),
correct switch, cables and connectors.
NN-GS597M
or