Sharp LC-46X8E/S/RU, Service Manual

Page: 47 / 166

LC-46X8E/S/RU
4 – 7
The audio signal is not output (3)
The audio signal of MONITOR is not output from EXT2 (SCART2).
TERMINAL UNIT:
Is audio signal (L/R) sent to pins (3, 1) of SCART2 (SC503)?
YES Check the connection to SCART2 and external devices.
NO
Is S2-MUTE signal [MAIN_UNIT pin (91) of IC9101 (CPLD)] at
H? YES Check the peripheral circuits of IC9101 and S2-MUTE signal.
(Q501, Q503, etc.)
NO
Is audio signal (L/R) sent to pins (3, 13) of IC7510 (SW)? YES Check the line between IC7510 and SC503.
(Q506, Q505, etc.)
NO
Is audio signal (L/R) input to pins (1, 12) of IC7510 (SW)? YES Check IC7510 or peripheral circuits.
(SC_AUD_SEL signal, etc.)
NO
Is audio signal (L/R) output from pins (40, 41) of IC1404
(CODEC)? YES Check the line between IC7510 and IC1404.
(IC1405, etc.)
NO
Check IC1404 and its peripheral circuits.
The audio signal is not output (4)
No audio signal output from AUDIO_OUTPUT terminal.
TERMINAL UNIT:
Is audio signal (L/R) output from pins (2, 4) of audio output termi-
nal (J503)?
YES Check the connection to J503 and external devices.
NO
MONITOR_MUTE signal [pin (72) of IC506
(VIDEO_SELECTOR)] or MUTE-A_ALL signal [pin (55) of
IC2002 (UCON)] will be “H”? YES This signal should be “L”.
Check IC506, IC2002, and its peripheral circuits.
NO
Is the audio signal (L/R) output from pins (40, 41) of IC1404
(CODEC)? YES Check the line between IC1404 and J503.
(IC1405, Q509, Q510, etc.)
NO
Check IC1404 and its peripheral circuits.