LG HDR688X, Service Manual

Page: 22 / 175

3-10
7. NO TUNER AUDIO OUTPUT
TU701 pin 16 (SIF) :
Is there a signal?
C928,C963 :
Is there a signal?
IC903,904 pin 7 :
Is there a signal?
Replace IC803
CHECK
IC903,904 pin 6 (12V)
YES
YES
IC803 pin 20, 24, 23, 27
Is there a signal?
YES
IC901 pin 34 Or R999
(reset “H”) :
YES
X901 (24.576MHz) clock
oscillated ?
R902,R913,R997 :
R962,R978 (I
2 C) :
YES
YES
C901 pin 173 & R903 :
Is there a signal ?
When playing DISC,
no Audio output
YES
YES YES
NO
CHECK
IC 803 pin 2,4 (VCC) : 12V
Pin 32,33 (SCL/SDA) :
NO
CHECK
IC1302 Reset Circuit
NO
NO
NO
IC1101 DEFECT
CHECK
IC901 power 3.3V & 1.8V
IC901 DEFECT
YES
A
B
A
B
Only “P Model”
Only “Without SCART Model”