LG LH-CX640 Series Service Manual page 35

3-18
(B)
No
Sound
No
Sound.
Check
the
Vcc of
IC751
Pins1,
11,
19,
22,
33.
YES
Check
5.2V
Line.
NO
Check
the
Tuner
SiF
signal
at
IC751
Pin2.
YES
Checkthe
oscillator
of
IC751
Pins5,
6.
YES
Check the
Audio
of
IC751
Pins30,
31.
YES
Check the
Audio
of
IC801
Pins2,
3.
YES
Check the
Audio
of
IC801
Pins16,
17.
YES
Check the
Audio
of
IC802
Pins22,
26.
YES
Check the
Signal
flow
from
IC802
Pins22,
26,
SC901
Pins1,
3.
YES
Check
the
Tuner
SIF of
TU701
Pin22.
NO
Replace
X751
NO
Check
the
IIC
Clock
and
Data
at
IC751
Pins12,
13.
NO
Checkthe signal
flow
from
IC751
Pins30,
31 to
IC801
Pins2,
3.
NO
Check
the
IIC
Clock
and
Data
at
IC801
Pins42,
43.
NO
Check
the
signal
flow
from
IC801
Pins16,
17 to
IC802
Pins10,
16.
NO