Troubleshooting - Samsung CM1319 Service Manual

6. Troubleshooting

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
LEAD WIRES 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
Oven is dead.
Fuse is OK.
No display and
no operation.
No display and no
operation Fuse is blown.
(10A, 1.6A)
Oven does not accept
key input (Program)
(CM1929/1629/1329)
Timer starts countdown
but no microwave
oscillation.
(No heat while oven
lamp and fan motor
turn on.)
PRECAUTION
CAUSE
1. Open or loose lead wire harness
2. Open thermal cutout (Magnetron, cavity)
3. Open low voltage transformer
4. Defective Ass'y PCB
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)
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.
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
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
CORRECTIONS
Check fan motor when thermal cutout
is defective.
Check Ass'y PCB when L.V.T is
defective.
Check adjustment of primary, interlock
monitor, door sensing switch.
Refer to operation procedure.
Replace PCB main.
Adjust door and latch switches.
Check high voltage component
according to component test
procedure and replace if it is
defective.