Service manual

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!
A5. No Sound (Test signal: )
YES
YES NO
Check that ICA3 Pin 7 is approximately 12V
Check that ICA1 Pin 3 is
approximately 9V
Check that ICM20 Pin4 is
Low voltage
YES NO
Check ICM20
Pin5,6,7,8 is12V
Failure point
1.JA1 failure
2.ICM10 failure
Check ICA2 pin11
Pin15 signal is
FIG 19.
Check ICA1 pin2
is about 5V
NOYES
YES
NO
Check ICA5,ICA6 pin4 is
about 5V
Failure point
1. QA6 or QA7 failure
2. ICA3 failure
YES
NO
Check ICA3 pin4,6
is FIG20.
Failure point
1.ICA1 failure
2.ICM10 failure
ICA5 or ICA6 failure
ICM10 failure
YES
NO
NO
ICM20 failure
ViewSonic Corporation
Confidential – Do Not Copy
VG800b
48
1 Vrms sine waveform