LG LRFD22850ST Service Manual page 29

MOTOR OFF
MOTOR ON
2.2 Cooling motor driving circuit (machine room)
1. This circuit makes standby power 0
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.
I C 1
(MICOM)
part
a
2V or less
13V~15V
by cutting off power supplied to ISs inside of the fan motor in the fan motor OFF .
MOTOR OFF 2V or less
MOTOR ON 13V~15V
R43
330J
R40
4.7KJ
R41
3.9KJ
35
P14
(PPG)
R42*
10KJ
32
P11
(INT1)
RJ1*
part
b
0V
0V
Part
a
Q4
D8
KTB1151
FR107
L4
1mH
R44
1.5KJ
1/2W
CE12
D9
Q5 220uF
FR107
KTC3198 /25V
R45
2KJ
- 29 -
part
c
5V
2V~3V
part
b
0V
0V
CON4
A
4
CC19*
223
3 4
5
C-FAN
1
R46
4.7KJ
6
CC20*
102