LG LDC22720 Series, Service Manual

Page: 23 / 43

3. Buzzer Drive Condition Check
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OFF
IC1 ( ) 0 V
IC1 ( ) 0 V
Measure-
ment Location
Condition
0 V
5 V
0 V
5 V
0.5 s 0.5 s
2.63 kz (Beep~) OFF
0.05 s 0.1 s 0.2 s 2 s
0 V
5 V
0 V
5 V
2.63 kz (Ding~) 2.21 kz (Dong~)
A
B
Tone (Ding~Dong~) when the button on
the display is pushed.
Alarm for open door
(beep-beep-beep)
2.2 Cooling motor driving circuit (machine room)
1. This circuit makes standby power 0 by cutting off power supplied to Iss inside of the fan motor in the fan motor
OFF.
2. This circuit prevents over-driving the fan motor by cutting off power applied to the fan motor in the lock of fan motor
by sensing the operation RPM of the fan motor.
part part
MOTOR OFF 2V or less 0V
MOTOR ON 13V~15V 0V
a b