Sharp TU-X1U Service Manual page 49

Is the audio output from the monitor set at "VARIABLE" or
"FIXED" on the menu screen?
Does the I2S signal come from pins (AL24)(DSP_MCLK2),
(L33)(DSP_BCKIN2), (M30)(DSP_LRCK2), (L32)(DSP_SDIN2)
of IC8001 (CPU) to pins (10), (9), (8), (12) of IC1403 (CODEC)
Does the audio signal come from pins (24)(LINE_L) and (25)
(LINE_R) of IC1403 to pins (2)(L) and (4)(R) of J602?
No monitor audio output
YES
YES
NO Check the I2C line (SCL0/SDA0) and IC1403.
NO Check IC8001 and IC1403, and their peripheral circuits.
NO Check the line between IC1403 and J505 and their peripheral
circuits.
IC1403 pin (24)(L)
P1401 pin (9)
P601 pin (9)
J602 pin (2)
Check the LINE_MUTE line and its peripheral circuits (Q1310
thru Q1311, etc).
4 – 22
pin (25)(R)
pin (11)
pin (11)
pin (4)
TU-X1U