Sharp LC32SB27U - LC - 32" LCD TV Service Manual page 61

No INPUT-5/6/7 (HDMI) audio.
If no video appears, refer to "No external input video (HDMI)
[INPUT-5/6/7]".
Is there the SPDIF signal output (OPT_OUT) at pin (J3) of IC8001 (CPU)?
YES
Is there the SPDIF signal (OPT_OUT) input at pin (2) of IC1304 (SPDIF-BUFF &
MUTE)?
YES
Is there the MUTE signal input at pin (1) of IC1304? (usual: High, Mute: Low)
YES
Is there the SPDIF signal input at pin (1) of D1306 (OPTICAL OUTPUT)?
YES
Check the speakers and the optical cable.
No audio signal at Digital Audio Output terminal (Analog sound heard)
LC-32D47U/LC-32SB27U/LC-C3237U
No audio at digital broadcast signal reception.
If no video appears, refer to "No video at digital broadcast signal reception".
NO Check the IC8001 and its peripheral circuits.
NO Check the line between IC8001 and IC1304.
NO Check the MUTE_A_ALL and AC_DET signals,
and their peripheral circuits (Q1304, D1310,
etc).
NO Check D1306 and its peripheral circuits.
No optical output under the following conditions
as per HDMI requirements.
* Audio contents protected.
* Audio frequency beyond 48kHz.
* Audio bit length beyond 16bits.
6 – 11