Sharp LC-37GP1U Service Manual page 42

LC-32GP1U/LC-37GP1U 1st
No audio at digital broadcast signal reception
Move the sound volume key.
Does the volume icon indi-
cate the speakers?
NO
Are there the IF_OUT_N
and IF_OUT_P signal out-
puts at pins (20) and (19) of
tuner (TU1101)?
YES
Are there the IF_OUT_N
and IF_OUT_P signal inputs
at pins (11) and (10) of
IC8601 (DEMODULATOR)?
YES
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)?
YES
Is the communication
between IC8101 and IC1404
(DAC) as specified?
(DTV_I2SMCLK/DTV_I2S/
SCLK/DTV_I2SLRCLK)?
YES
Are the audio signal outputs at pins (38) (L) and (39) (R) of IC1404?
Are the audio signal outputs at pins (11) (L) and (14) (R) of connector (SC1301) on the MAIN unit?
Are the audio signal inputs at pins (11) (L) and (14) (R) of connector (P2704) on the TERMINAL unit?
Are the audio signal inputs at pins (5) (L) and (3) (R) of IC2701 (STEREO_AMP)?
Is the audio output from IC2701 as specified?
Check the P2703 connector, speakers and their peripheral circuits.
YES Set the audio output to
"FIXED".
NO Check the tuner (TU1101)
and its peripheral circuits.
Replace as required.
NO Check the line between
tuner (TU1101) and IC8601,
and their peripheral circuits
(filter circuit, etc.).
NO Check the line between
IC8601 and IC8101, and
their peripheral circuits.
NO Check the line between
IC8101 and IC1404, and
their peripheral circuits.
YES
YES
YES
YES
YES
No audio (4)
No audio at UHF/VHF broadcast signal reception
Is the audio output selected
for "VARIABLE" on the
menu screen?
NO
Is there the SIF signal output
at pin (15) of tuner
(TU1101)?
YES
Is there the SIF signal input
at pin (21) of IC1401
(SIF_DECODER)?
YES
Are the audio signal outputs
at pins (30) (L) and (29) (R)
of IC1401?
YES
Are the audio signal inputs
at pins (51) (L) and (52) (R)
of IC1404?
YES
6 – 10
YES Set the audio output to
"FIXED".
NO Check the tuner (TU1101)
and its peripheral circuits.
Replace as required.
NO Check the line between
tuner (TU1101) and IC1401,
and their peripheral circuits
(Q1102, Q1103, etc.).
NO Check IC1401
(SIF_DECODER) and its
peripheral circuits. Replace
as required.
NO Check the line between
IC1401 and IC1404, and
their peripheral circuits.
NO Check IC1404 and its
peripheral circuits.
NO Check the line between
IC1404 and SC1301, and
their peripheral circuits.
NO Check the SC1301 and
P2704 connectors.
NO Check the line between
P2704 and IC2701, and
their peripheral circuits
(AMP_MUTE line).
NO Check IC2701 and its
peripheral circuits.