Sony KDP-51WS550 Training Manual page 44

Also, input to IC1502 is audio from the ATSC Tuner, Memory Stick, i.LINK® and DVI through switching ICs
IC1504 and IC1505. The control from the switching function in these ICs comes from the serial porter at IC1501/
pin74 (the video switcher IC).
The selected audio from the main switcher IC1502 is then sent to the MA-board and applied to the Audio Processor
IC0302.
The Monitor L/R output also is output from the AV Switch IC1502/pins 33 and 35, applied to Q1504 (buffer) and
Q1503 (buffer), and then to J1503.
The audio processor IC0302 takes the main audio input and produces a main L/R output. These outputs are
then passed to the A-board where they are applied to the audio amplifier IC2000/pins 10 and 18.
The VAR/FIX L/R audio is output from Audio Processor IC0302/pins 7 and 32. Speaker outputs can be viewed
at CN527/pins 3, 7, 1 and 5.
Troubleshooting Tip:
The audio circuitry can be diagnosed for defects by using particular inputs and monitoring particular outputs for
audio.
1) Input a signal from the ATSC Tuner, Memory Stick or i.LINK® sections and the Q-box, IC1601, IC1504,
IC1505, IC1502, IC0302 and IC2000 will all be tested. Basically, all audio circuitry is tested.
2) Input a signal from the DVI input, and the Q-Box and IC 1601 are bypassed
3) Input a signal from V1-6, Main, or Sub Tuners and Q-Box, IC1601, IC1504 and IC1505 are bypassed.
4) To bypass the Audio Processor, input a signal to any input and monitor the Monitor Output (IC1502/pins
33 and 35) for audio.
5) To bypass the Audio Amp IC2000, input a signal to any input and monitor the Vari/Fixed (IC0302/pins 7
and 32) output for audio.
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8. AX-1 Audio Circuit