Checking The Audio Circuit - NEC MultiSync LCD1550ME Service Manual

12. Checking the audio circuit

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