Sharp Aquos LC-37D90U, Service Manual

Page: 94 / 208

LC-37D90U
6 – 15
No audio signal at DIGITAL AUDIO OUTPUT terminal (Analog sound heard)
No INPUT-3/4 (HDMI) audio No audio at digital broadcast signal reception
If no video appears, refer
to “No external input video
(HDMI) [INPUT-3/4]”. Are there the IF_OUT_N
and IF_OUT_P signal out-
puts at pins (20) and (21) of
tuner (TU1101)?
NO
Check the tuner
(TU1101) and its
peripheral circuits.
Replace as required.
YES
Is the SII9011_MUTE line
as specified?
NO
Check Q1301, IC1303
and their peripheral cir-
cuits. Are there the IF_OUT_N
and IF_OUT_P signal
inputs at pins (10) and (11)
of IC8601 (DEMODULA-
TOR)?
NO
Check the line
between tuner
(TU1101) and IC8601,
and their peripheral
circuits (filter circuit,
etc.).
YES YES
Does the HDMI_SPDIF
signal come from pin (70)
of IC1508 to pin (2) of
IC1403 (CODEC)?
NO
Check the line between
IC1508 and IC1403 and
their peripheral circuits. Do the US_TS_CLK/DATA/
EN/PKTSYNC signals
come from pins (51, 59, 63
and 66) of IC8601 to pins
(D11, A9, C10, B10) of
IC8101 (CPU/DECODER),
respectively?
NO
Check the line
between IC8601 and
IC8101, and their
peripheral circuits.
YES
YES
Is the DTV_SPDIF signal
output at pin (R33) of
IC1801?
NO
Check IC8101 and its
peripheral circuits.
YES
YES Is the DTV_SPDIF signal
input at pin (5) of IC1403?
NO
Check the line
between IC8101 and
IC1403, and their
peripheral circuits.
Is there the SPDIF signal
output at pin (23) of
IC1403 (CODEC)?
NO
Check IC1403 and its
peripheral circuits.
YES
Is there the SPDIF signal
input at pin (1) of IC1408
(SPDIF_FUFF.)?
NO
Check the line between
IC1403 and IC1408 and
their peripheral circuits.
No monitor audio
YES