Checking The Audio Circuit - Acer AL702 Service Manual

12. Checking the audio circuit

1) Speaker cable disconnection
2) Speaker failure
Trou bl e Sh ooti ng
Is a cable with the
host PC connected?
Failure point
OK NG
Audio cable disconntction.
Aren't the setups of the
host PC a minimum and off?
Failure point
NG
OK
The setup of the host PC is changed.
Is correct output waveform
being inputted from JK011
pin 2, 3 of the host PC?
Failure point
NG
OK
Audio cable disconntction.
Is the waveform which is the
same as JK011 being
inputted to I001 pin 4, 9?
NG
1) Printed wire broke between JK011 pin 2, 3 and I001 pin 4, 9.
OK
2) R040, R041 open.
3) R042, R043 short.
4) C040, C041 open.
Is output wavefrom being
outputted in I001 pin 14, 17?
NG
Is 15V supplied to I001 pin 15, 16?
OK
NG
Failure point
OK
Is mute/STD-BY low level at pin 11,
pin 12.
Proceed section 11 "Checking
NG
OK the operation of CPU".
Is Variable DC volume
control at pin 6.
NG
Check I002 pin 8 is 5V DC.
OK
Failure point
I001 failure.
Failure point
Proceed section 9.1 "No power on".
NG
Proceed section 9.1 "No power on".
OK
Proceed section 11 "Checking
the operation of CPU".
A L C502
Page 15