LG LPC-LM440A/X Service Manual page 25

• POWER IC TROUBLESHOOTING
1)2CH(L/R)
Check Signal in Check Signal in
IC901 Pin6,Pin8 IC901 Pin6,Pin8
YES
Check IC 901 PIN10(Mode1) ©
MAIN Vcc
Check IC 901 PIN11(SVR) © MAIN Vcc/2
YES
OUTPUT O.K
2)SUB-WOOFER
Check Signal in
IC901 Pin9,Pin12
YES
Check IC 901 Pin5(Mode2) ©
MAIN Vcc
YES
OUTPUT O.K
Check Signal in
IC601Pin3,Pin5
YES
OUTPUT O.K
NO
Check the IC301 Pin12, Check the IC301 Pin12,
Pin17 Pin17
NO
Check Micom port 99(Mode1_control)©"0.6V "
NO
Check the Low-pass
Block(IC802)
NO
Check Micom port
97(Mode2_control) © "HIGH"
NO
Check the Q601,Q651
Check IC601 Pin8(6.8V)
If head phone jack is inserted
1) Micom port 48(H/P IN) © "Low "
2) Micom port 9(AMUTE) © "High "
3) IC901 Pin 5&Pin10 © "Low "
- 2-16 -
NO
Check Q252,Q253 Check Q252,Q253
Check Q271,Q272
NO
Check IC802 Pin 5
Check IC802 Pin 8