Sharp 4T-B70CJ1U Service Manual page 31

2-5. No audio heard (1)
No sound in the UHF/VHF reception.
↓ Yes
Is the IF output from the tuner pin(6,7,8,9)
of TU1102 as specified ?
↓ Yes
Is there IF input at pin K1 & K2 of IC3301 ?
↓ Yes
Is there audio 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 IC1702normal?
↓ 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 TU1102 and its peripheral circuits.
NO
Check the circuit between TU1102 &
NO
IC3301.
Check connection between IC3301 and
NO
IC1702 and its peripheral circuits.
Check IC1702 and its peripheral circuits.
NO
NO
Check circuit between IC1702 & P504.
4 - 29