Daewoo KQG-8B7R5SSC, Service Manual, Page: 30 / 37

29
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
STATE
POINT
A B
RELAY 2 ON -5VDC GND
RELAY 2 OFF GND -12VDC
4. When there is no grill oscillation.
* Cause :
RELAY 3
does not operate. •refer to Circuit Diagram (Point 6)
- Check method
5. When the door is opened during operation, the count down timer does not stop.
→
refer to Circuit Diagram (Point 1)
-Check method
6. 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.
STATE
POINT
A B
RELAY 3 ON -5VDC GND
RELAY 3 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
1
T
T:20ms(50Hz)
0V
-5V