19
6. Troubleshooting
PRECAUTION
1.
CHECK GROUNDING BEFORE CHECKING FOR TROUBLE .
2.
BE CAREFUL OF THE HIGH VOLTAGE CIRCUIT .
3.
DISCHARGE THE HIGH VOLTAGE CAPACITOR .
4.
WHEN CHECKING THE CONTINUITY OF THE SWITCHES OR TRANSFORMER, DISCONNECT ONE
LEAD WIRE FROM THESE PARTS AND THEN CHECK CONTINUITY WITHOUT THE POWER SOURCE
ON . TO DO OTHERWISE MAY RESULT IN A FALSE READING OR DAMAGE TO YOUR METER .
5.
DO NOT TOUCH ANY PART OF THE CIRCUIT OR THE CONTROL CIRCUIT BOARD, SINCE STATIC
DISCHARGE MAY DAMAGE IT . ALWAYS TOUCH GROUND WHILE WORKING ON IT TO DISCHARGE
ANY STATIC CHARGE BUILT UP .
6-1 Electrical Malfunction
SYMPTOM
CAUSE
CORRECTIONS
Oven is dead .
Fuse is OK .
No display and no
operation at all .
1 . Open or loose lead wire harness
2 . Open thermal cutout (Magnetron)
3 . Defective Ass’y PCB
Check fan motor when thermal cutout
is defective .
No display and no
operation at all . Fuse is
blown .
1 . Shorted lead wire harness
2 . Defective primary latch switch
(NOTE 1)
3 . Defective monitor switch
(NOTE1)
4 . Shorted H .V .Capacitor
5 . Shorted H .V .Transformer
(NOTE2)
Check adjustment of primary,
interlock monitor, power relay, door
sensing switch .
NOTE
1
: All of these switches must be replaced at the same time .(refer to
adjustment instructions) Check continuity of power relay contacts and if it
has continuity, replace power relay also .
NOTE
2
: When H .V .Transformer is replaced, check diode and magnetron also .
Oven does not accept
key input (Program)
1 . Key input is not in-Sequence
2 . Open or loose connection of membrane
key pad to Ass’y PCB
3 . Shorted or open membrane panel
4 . Defective Ass’y PCB
Refer to operation procedure .
Replace PCB main .
Timer starts countdown
but no microwave
oscillation .
(No heat while oven lamp
and fan motor turn on .)
1 . Open or loose connection of high
voltage circuit especially magnetron
filament circuit
NOTE : Large contact resistance will
bring lower magnetron filament
voltage and cause magnetron to
lower output and/or intermittent
oscillation .
2 . Defective high voltage components
H .V .Transformer H .V . Capacitor
H .V .Diode, H .V .Fuse Magnetron
Adjust door and latch switches .
Check high voltage component
according to component test
procedure and replace if it is
defective .
Summary of Contents for CM1929
Page 1: ...Mod CM1929 Production code CM 1929A 08 2012 ...
Page 4: ...3 1 Precaution ...
Page 22: ...21 6 Troubleshooting 6 1 Electrical Malfunction Continued ...
Page 23: ...22 6 Troubleshooting 6 1 Electrical Malfunction Continued ...
Page 24: ...23 6 Troubleshooting 6 1 Electrical Malfunction Continued ...
