Sharp 4T-B70CJ1U Service Manual page 32

2-6. No audio heard (2)
No external audio heard<INPUT3>
Is there the L-ch audio signal input from pin
(4) of input terminal J502 to pin (D4)
ofIC3301?
Is there the R-ch audio signal input from pin (1) of
inputterminal J502 to pin (D5) of IC3301?
↓ Yes
Is there the signal output at pin
(AL28),(AL27),(AK28), (AM27) of IC3301 ?
↓ Yes
Is there signal input at pin(1),(2),(3),(4) of
IC1702?
↓ Yes
Is the L-ch audio signal output at
pin(8),(9),(12),(13) of IC1702 normal ?
Is the R-ch audio signal output at
pin(18),(19),(22),(23) of IC1702 normal ?
↓ Yes
Are the audio signal L-ch and R-ch output at
(3)/(4) and (1)/(2) of P504 normal?
↓ Yes
Check speakers and their peripheral circuits.
4T-B70CJ1 TROUBLE SHOOTING
Check IC3301 and its peripheral circuits.
NO
Check connection between IC3301 and
NO
IC1702 and its peripheral circuits.
Check IC1702 and its peripheral circuits.
NO
Check circuit between IC1702 & P504.
NO
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