Audio Signal Processing Stage - Sanyo PLC-XF60 Service Manual

Chassis Description & Troubleshooting

3. Audio Signal Processing Stage

Audio inputs for DVI and VGA terminal are sent from terminal <PC1 AUDIO> to pins 1 and 30 of IC9501<AUDIO SE-
LECTOR & VOLUME CONTROL>. Audio inputs for BNC terminal are sent from terminal <VIDEO AUDIO> to pins 4
and 27 of IC9501. Audio inputs for RCA terminal are sent from terminal <PC2 AUDIO> to pins 2 and 29 of IC9501. The
input selection is carried out by the IIC bus signal "IICSCL/IICSDA" applied on pins 13 and 14, and selected signals
are output from pins 10 and 21. IC801<CPU> outputs the IIC bus signal from pins 216 and 217, and sends to IC9501.
The input selection, sound volume and sound quality are controlled at IC9501 by the IIC bus signal.
The signals applied on pins 2 and 5 of IC5001<AUDIO OUTPUT> are amplified and output from pins 10 and 7 as the
signal to drive the speakers. The "AUDIO_MUTE" signal is output from pin 50 of IC4802<I/O EXPANDER> and ap-
plied to pin 3 of IC5001 through Q5004. When the level of pin 3 becomes "L", the sound mute is on.
[NO SOUND]
Points of Repair
Check that it does not reproduce the sound with all the input mode.
If no sound with a certain input mode, the problem may be between input terminal and IC9501<AUDIO SELEC-
TOR>.
If no sound with all the input mode, check the below check list.
- Check that the output signal is correct at pins 10 and 21 of IC9501.
- Check that the output signal is correct at pins 2 and 5 of IC5001.
- Check that the mute signal is correct at pin 3 of IC5001. MUTE on: "L"
- Check that the output signal is correct at pins 7 and 10 of IC5001.
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