LG HT904TA Service Manual page 22

. AUDIO µ-COM Circuit(DVD & AMP)
Power On.
YES
Does
CD/DVD appear at
FLD?
YES
Does
NO
Reading appear
at FLD?
YES
Does
NO
no Disc or Time
appear at
FLD?
YES
Check
if DVD/CD insert
is OK.
NO
Check Power.
YES
Check DVD Module.
YES
Check SMPS.
NO
Does
NO
it appear DVD Error
at FLD?
YES
Check
NO
power part of Main
B/D.
YES
Check
NO
oscillator of
X100.
YES
Check
NO
if IC101 Pin29
is high.
YES
Check if
NO
IC101 Pins 14, 40, 55, 89
are high(5V).
YES
Check
NO
if IC101 Pin58
is high.
YES
Replace IC101.
2-
Does AV1,
YES
TV AUDIO, AV1 OPT and
FM 87.5 appear
at FLD.
NO
Refer to SMPS.
Refer to oscillator circuit.
Check IC101 Pin29
reset waveform.
Check 5V line.
Check power section
circuit.
OK