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

Page: 46 / 166

LC-46X8E/S/RU
4 – 6
The audio signal is not output (1)
The audio signal of UHF/VHF and DTV is not output from EXT1 (SCART1).
TERMINAL UNIT:
Is audio signal (L/R) output from pins (3, 1) of SCART1 (SC502)?
YES Check the connection to SCART1 and external devices.
NO
Is S-MUTE signal [MAIN_UNIT pin (93) of IC9101 (CPLD)] at H? YES This signal should be “L”.
Check the peripheral circuits of IC9101 and S-MUTE signal.
(Q502, Q504, etc.)
NO
Is audio signal (L/R) output from pins (24, 22) of IC1402 (SOUND
MULTIPLEX DECODER)? YES Check the line between SC502 and IC1402.
(Q508, Q507, IC1407, etc.)
NO
Check IC1402 and its peripheral circuits.
The audio signal is not output (2)
The audio signal of UHF/VHF and DTV is not output from EXT2 (SCART2).
TERMINAL UNIT:
Is audio signal (L/R) output from 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 This signal should be “L”.
Check the peripheral circuits of IC9101 and S2-MUTE signal.
(Q501, Q503, etc.)
NO
Is audio signal (L/R) output from 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 (2, 15) of IC7510 (SW)? YES Check IC7510 or peripheral circuits.
(SC_AUD_SEL signal, etc.)
NO
Is audio signal (L/R) output from pins (24, 22) of IC1402 (SOUND
MULTIPLEX DECODER)? YES Check the line between IC7510 and IC1402.
(IC1407, etc.)
NO
Check IC1402 and its peripheral circuits.