AOC Vibrant VL7A9DA Service Manual page 36

6 D). AUDIO-MODULE Trouble shooting chart
I.) NO VOICE OUTPUT
Plug-out the DC power , make sure
the monitor is in OFF status .
Use OHM-METER measure U1 pin 2, 4
(channel-A ) is speaker well connected?
Measure U1 pin 10,12 ( channel B) is speaker
well connected ?
]
Plug-in the DC power, set the monitor
ON status .
Check U1 pin 1 = VCC 12V
Check U1 is work properly?
Check U1 pin 5 standby-bias
voltage around 4 V ?
Check U1 pin 9 volume -bias
around 1 V ?
Check Audio cable and J4 is well connected
YES
YES
YES
YES
NG
Check J1,J2 is well connected?
Measured J2 pin 4,5 & 2,3 is
well connected ?
Check is speaker open circuit ?
NG
Check R10,R11 & J5, S1 is open
circuit?
NG
Check R4 is open circuit?
NG
Check R7 , VR1
YES