Sharp AQUOS LC-20D42U, Service Manual

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32
LC-20D42U
TROUBLESHOOTING TABLE
(Continued)
No audio output during UHF/VHF reception
Yes
No
No
Yes
No
Yes
No
Yes
No
Yes
Yes
Check IC1404 and peripheral circuits.
Are the DSP_LRCK,DSP_BCKIN,DSP_SDIN1,
DSP_MCLK,DSP_SDOUT1,DSP_SDOUT2 signals
sent from IC1404 to IC1407(DSP) normally?
Check between pins 29 and 30 (SC2_OUTL/R) of
IC1401 and pins 51 and 52 of IC1404(CODEC)
Check the filter circuits (Q1102-3) and peripheral
circuits
Check the tuner and peripheral circuits. Is SIF output from the tuner (TU1101_Pin15) normal?
Is input signal fed to pin21 (SOUNDIF 1)of IC1401(SIF
Demodulator) normal?
Are audio signals from pins 29 and 30 (SC2_OUTL/R) of
IC1401 to pins 51 and 52 of IC1404 (CODEC) normal?
Check the connector (P2703) of AV_UNIT and around the
speakers.
Are audio outputs (A-OUT_L/R) of pins 38 and 39 of
IC1404 normal?
Is audio input from pins 38 and 39 of IC1404 to pin 3 and 5
of IC2701 (STEREO_AMP) normal?
Check the circuits between pins 38 and 39 of
IC1404 and pins 3 and 5 of IC2701. (MUTE
cercuits:Q1307,Q1314,Q1313)
No
Yes
Check IC2701 and peripheral circuits
Is audio output from IC2701 normal?
No monitor audio output
Yes
No
No
Yes
No
Yes
Check IC1408 and peripheral circuits.
Check IC1404 and peripheral circuits.
Reset monitor audio output to "Fixed". Is monitor audio output set to "Variable"?
Are audio output pins 40 and 41 of IC1404 (CODEC)
normal?
Are audio output pins 7 and 1 of IC1408 (Buffer_AMP)
normal?
Check between IC1408 and MONITOR OUTPUT terminal
(J501,J502).