No Sound (Test Signal: 1R.m.s Sine Waveform) - ViewSonic VX800-3 - 18" LCD Monitor Service Manual

4.5 No Sound (Test signal: 1r.m.s sine waveform)

Check that ICA3 Pin 7 is approximately 12V
YES
Check that ICA1 Pin 3 is
approximately 9V
YES
Check ICA2 pin11
Pin15 signal is
FIG 17.
YES YES
Check ICA3 pin 4, 6
is FIG18.
YES
Check ICA5, ICA6 pin 4 is
about 5V
YES
ICA5 or ICA6 failure
ViewSonic Corporation
Check that Q306 Pin 4 is
NO
Check ICA1 pin2
is about 12V
NO
NO
IC400 pin 125 failure
NO
Low voltage
YES
Check Q306
Pin5, 6, 7, 8 is12V
NO
Q306 failure
Failure point
1.ICA1 failure
2.IC400 pin 123 failure
NO
Failure point
1. QA6 or QA7 failure
2. ICA3 failure
Confidential – Do Not Copy
NO
Failure point
1. JA1 failure
2. IC400 pin123 failure
VX800-3