Sharp LC-42D65U Service Manual page 55

Is the audio output from the monitor set at "VARIABLE" or "FIXED" on the
menu screen?
Are there the audio signal outputs at pins(24)(LINE_L) and (25)(LINE_R) of
IC1403(CODEC)?
Does the audio signal come from pins(24)(LINE_L) and (25)(LINE_R) of
IC1403 to pins(4)(L) and (2)(R) of J505?
No monitor audio output
YES
YES
NO Check the I2C line(SCL0/SDA0) and IC1403.
NO Check IC1403 and its peripheral circuits.
NO Check the line between IC1403 and J505 and their
peripheral circuits.
Check the LINE_MUTE line and its peripheral circuits.
(Q1310 thru Q1311, etc.)
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LC-42D65U