Sharp LC-70LE740E Service Manual page 131

LC-60/70LE740E/RU,741E/S,743E,60LE840E/RU,841E/S,843E,80LE645E/RU,646E/S,648E (1st Edition)
No sound from DIGITAL AUDIO OUTPUT terminal.
Does audio signal output from pin [1] of sound output terminal
(D527)?
Does audio signal output from pin [4] of IC503?
Is AUDIO_MUTE (MUTE_A_ALL) [23 pin] of IC2001 (UCOM) at
"H"?
Does audio signal input to pin [2] of IC503?
Does audio signal (OPT_OUT) output from pin [AA31/
CPU_ASPDIF] of IC3303 (Digital AV decode & Main CPU)?
Check IC3303 and its peripheral circuits.
Does not the sound of the audio signal output to HDMI1 go out?
Does audio signal output from pin [14] of SC1503 (HDMI1 termi-
nal)?
Does audio signal output from pin [39/HECP] of IC1504 (HDMI-
SW)?
Does audio signal input to pin [36/SPDIF_IN] of IC1504?
Does audio signal (HDMI_OPT_OUT) output from pin [AA31/
CPU_ASPDIF] of IC3303 (Digital AV decode & Main CPU)?
Check IC3303 and its peripheral circuits.
No sound from external output device (3)
NO
NO
NO
NO
NO
No sound from external output device (4)
NO
NO
NO
NO
YES Check D527 and peripheral circuits.
YES Check the line between IC503 and D527.
YES Check the peripheral circuits of IC503 and AUDIO_MUTE.
(Q505 etc...)
YES Check IC503 and peripheral circuits.
YES Check the line between IC3303 and IC503.
YES Check SC1503 and peripheral circuits.
YES Check the line between IC1504 and SC1503.
YES Check IC1504 and peripheral circuits.
YES Check the line between IC3303 and IC1504.
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