Daewoo KOR-637V0A, Service Manual, Page: 31 / 37

3. When there is no microwave oscillation
1) When pressing START button, oven lamp does not turn on.
Fan motor do not rotate, but cook indicator in display comes on.
* Cause : RELAY 2 does not operate.
→
refer to Circuit Diagram (Point 3)
- Check method
2) When pressing START button, oven lamp turns on.
Fan motor and turntable rotate and cook indicator in display comes on.
* Cause : RELAY 1 does not operate.
→
refer to Circuit Diagram (Point 2)
- Check method
4. When the door is opened during operation, the count down timer does not stop.
→
refer to Circuit Diagram (Point 1)
-Check method
5. When the digital clock does not operate properly.
→
refer to Circuit Diagram (Point 5)
* If clock does not keep exact time, you must check resistor R16, 17 zener diode ZD1.
6. When pressing PURIFICATION button, UV lamp does not turn on,
but cook indicator in display comes on.
* Cause : RELAY 3 does not operate.
→
refer to Circuit Diagram (Point 6)
- Check method
30
STATE
POINT
A B
RELAY 2 ON -5VDC GND
RELAY 2 OFF GND -12VDC
STATE
POINT
A B
RELAY 1 ON -5VDC GND
RELAY 1 OFF GND -12VDC
STATE
POINT
A B
1) DOOR OPEN OPEN -5VDC
2) DOOR CLOSED CLOSE GND
CHECK NO METHOD REMEDY
1 Check the stage (ON, OFF) of the door open monitor switch by Replace door open monitor
resistance measurement. switch.
POINT WAVE FORM
A
T:16.67ms(60Hz)
STATE
POINT
A B
RELAY 3 ON -5VDC GND
RELAY 3 OFF GND -12VDC