Sharp LC-60LE740E Service Manual page 152

LC-60/70LE740E/RU,741E/S,743E,60LE840E/RU,841E/S,843E,80LE645E/RU,646E/S,648E
No sound output in all modes?
Do audio signals output from pins [Y30/CPU_AOLRCK, Y31/
CPU_AOBCK, Y32/CPU_AOMCLK, V27/CPU_AOSDATA0] of
IC3303 (Digital AV decode & Main CPU) ?
Do audio signals input to pins[5/AMP_MCLK ,6/
AMP_DATA_LR,, 7/AMP_BCLK, 8/AMP_LRCLK] of IC2703
(SP_AMP) ?
Do audio signals output from pins
[28/OUTML, 30/OUTPL, 12/OUTPR, 14/OUTMR] of IC2703 ?
DIs AMP_MUTE [pin(21)] of IC2703 at "H" ?
YES
Do audio signals input to pins[1&2/L-ch, 3&4/R-ch] of P2701 ?
YES
Check Speaker (right and left) and wire harness.
The sound is not emitted from the Speaker.
YES
YES
YES
YES
NO Check IC3303 and its peripheral circuits.
NO Check the line between IC3303 and IC2703.
NO Check IC2703 and its peripheral circuits.
NO Check the line between IC2703 and IC3303 & IC2001(UCOM).
(Q2701,D2701 etc...)
NO P2701 terminal and the peripheral circuit (L/C filter) are checked.
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