Sharp LC-40LE820UN Service Manual page 75

No INPUT-4/5/6/7 (HDMI) audio.
If no video appears, refer to "No external input video (HDMI)
[INPUT-4/5/6/7]".
Is there the SPDIF signal output (OPT_OUT) at pin (J28) of IC3302 (CPU)?
YES
Is there the SPDIF signal (OPT_OUT) input at pin (2) of IC503 (SPDIF BUFFER & SPDIF-MUTE)?
YES
Is there the MUTE signal input at pin (7) of IC503? (usual: High, Mute: Low)
YES
Is there the SPDIF signal input at pin (1) of D520 (OPTICAL OUTPUT)?
YES
Check the speakers and the optical cable.
No audio signal at Digital Audio Output terminal (Analog sound heard)
No audio at digital broadcast signal reception.
If no video appears, refer to "No video at digital broadcast signal
reception".
NO
Check the IC3302 and its peripheral circuits.
NO
Check the line between IC3302 and IC503.
NO
Check the MUTE_A_ALL and SPDIF-MUTE signals, and their peripheral cir-
cuits (Q505, D530, etc.).
NO
Check D520 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.
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LC-40/46/52/60LE820UN