LG LSRG309ST Service Manual page 52

CHECKING FLOW CHART BY FAILURE
Power On
4
Check the voltage of
Power PCB
Is the voltage as below?
PIN No. of CN10
PIN2 ~ PIN3(GND)
PIN4 ~ PIN3(GND)
PIN5 ~ PIN6
CN10 CN10 CN10 CN10 CN10 CN10 CN10
CN10 CN10 CN10 CN10 CN10 CN10
CN10 CN10 CN10 CN10
CN10 CN10 CN10 CN10 CN10
Yes
No
Replace the
Power PCB
Voltage
approximately
14.5~ 15.5[V]
approximately
-24 ~ -35[V]
approximately
AC 3.4~ 4.6 [V]
Power On
5
Is the voltage of Main
PCB's Vcc 4.5V ~ 5.5V?
Check the voltage between
pin2 and pin3 of IC2
3pin
3pin 3pin 3pin 3pin 3pin 3pin
3pin 3pin 3pin 3pin
3pin 3pin 3pin 3pin
3pin 3pin 3pin
6
Check the voltage of
Main PCB
Is the voltage as below?
PIN No. of CN9
PIN4 ~ PIN3(GND)
PIN5 ~ PIN6
1pin 1pin 1pin 1pin 1pin
1pin 1pin 1pin 1pin 1pin 1pin
1pin 1pin 1pin 1pin
1pin 1pin 1pin
Yes
Replace the Main PCB
10-3
No
Replace the
Main PCB
2pin(GND) 2pin(GND) 2pin(GND) 2pin(GND) 2pin(GND)
2pin(GND) 2pin(GND)
2pin(GND) 2pin(GND) 2pin(GND) 2pin(GND) 2pin(GND) 2pin(GND)
2pin(GND) 2pin(GND) 2pin(GND) 2pin(GND) 2pin(GND)
IC02 IC02 IC02
IC02 IC02 IC02 IC02
IC02 IC02 IC02 IC02 IC02 IC02
IC02 IC02 IC02 IC02 IC02
Replace the
No
harness
(CN9 to CN10)
Voltage
approximately
-24 ~ -35[V]
approximately
AC 3.4~ 4.6 [V]
CN9 CN9 CN9
CN9 CN9 CN9 CN9
CN9 CN9 CN9 CN9 CN9 CN9
CN9 CN9 CN9 CN9 CN9 CN9
CN9 CN9 CN9