LG LAN-8680MH Service Manual page 75

• AUDIO OUTPUT DEAD
CIRCUIT OUTPUT OF POWER AMP
AUDIO OUTPUT DEAD.
AUDIO OUTPUT FAILURE
YES
YES
CN102 CABLE IS
CN102 CABLE IS
PROPERLY
CONNECTED NORMAL?
CONNECTED?
YES
YES
DSP POWER INPUT
DSP POWER INPUT
IS NORMAL?
IS NORMAL?
(Q201,TP262 :1.8V
(Q201,TP262 : 1.8V
3.3V:T765).
3.3V: T765)
YES
YES
DSP OUTPUT IS
DSP OUTPUT IS
NORMAL?
NORMAL?
(IC202 PIN38/39/
(IC202 PIN38/39/
43/44)
43/44).
YES
YES
FREE AMP POWER
FREE AMP POWER
INPUT IS NORMAL?
INPUT IS NORMAL?
(IC418 PIN20,21, (IC418 PIN20,21,
34,35).
34,35)
YES
YES
POWER AMP
STBY /RESET
STBY /RESET
CIRCUIT OUTPUT IS
IS NORMAL?
NORMAL?
(TP673).
(TP673)
YES
YES
FREE AMP OUTPUT
FREE AMP OUTPUT
IS NORMAL?
IS NORMAL?
YES
YES
CHECK CONNECTOR.
CHECK CONNECTOR
• CHECK CABLE CHECK CABLE
NO
NO
CONNECTION.
CONNECTION.
• IF DEFECTIVE,
IF DEFECTIVE,
CHANGE CABLE.
CHANGE CABLE
CHECK 3.3V
CHECK 3.3V
NO
REGULATOR OF Regulator of
NO
POWER B/D IS
POWER B/D is
PROPERLY WORK
properly work.
(POWER:IC820).
POWER:IC820
NO
NO
CHECK OUTPUT CHECK OUTPUT
PIN SHORT. PIN SHORT
9V VOLTAGE CHECK
NO
9V Voltage Check
NO
(AUDIO_SUB_POWER
(Audio_sub_power
9V IC VOLTAGE
9V IC Voltage Check)
CHECK).
• CHECK TRANSISTOR.
CHECK TRANSISTOR
NO
NO
CONTROL (Q457,458)
CONTROL (Q457,458)
• CHECK MICOM PORT
CHECK MICOM PORT
(T543).
NO
NO
CHECK OUTPUT
CHECK OUTPUT
TERMINAL SHORT.
TERMINAL SHORT
- 9-7 -
(T543)