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5. When the digital clock does not operate properly.
→
refer to Circuit Diagram.
- Check method
POINT
A
B
STATE
1) DOOR OPEN
OPEN
5VDC
2) DOOR CLOSED
CLOSE
GND
CHECK NO
HETHOD
REMEDY
1
Check the stage(ON, OFF) of the door open monitor
Replace door open monitor switch.
switch by resistance measurement.
POINT
WAVE FORM
IC 1 PIN 8
❈
If clock does not keep exact time, you must check resistor R20 and zener diode ZD2.
T
T: 20 ms(50Hz)
5V
0V