Sharp LC-52SB57U - No Monitor Audio Output

LC-46SB57U/LC-52SB57U
6 – 14
No monitor audio output
Is the audio output from the monitor set at “VARIABLE” or “FIXED” on the menu screen?
YES
NO
Check IC8001 (CPU) and its peripheral circuits.
Are there the audio signal outputs at pins (N27) (PGA1OUT_L) and (N28) (PGA1OUT_R) of IC8001 (CPU)?
YES
NO
Check IC8001 (CPU) and its peripheral circuits.
Does the audio signal come from pins (N27) (PGA1OUT_L) and (N28) (PGA1OUT_R) of IC8001 to pins (4) (L) and (2) (R) of J505?
YES
NO
Check the line between IC8001 and J505 and their peripheral circuits.
Check the LINE_MUTE line and its peripheral circuits (Q1310/Q1311, etc.).
Check the connector (J505) and their peripheral circuits, and speakers and the Cable.