Sharp lc-42ad5e Service Manual page 40

LC-42AD5E/RU/S
No sound output in all modes.
Is the audio signal properly sent from pins (28) (L-ch) and (27)
(R-ch) of IC3002?
Is the audio signal of pins (3) (L-ch) and (5) (R-ch) of IC303 (OP-
AMP) sent properly?
Is the audio signal of pin (4) of IC301 (R-ch)/IC302 (L-ch)
(AUDIO-AMP) sent properly?
Is the audio signal output of pins (2, 1) (L-ch) and (4, 3) (R-ch) of
P301 (AUDIO-CONNECTOR) normal?
Check Speaker Box (right and left) and wire harness.
No audio output during UHF/VHF reception
Checklist:
1) Is the volume set to MIN or MUTE on the remote control? ••• Set the desired volume.
2) Are headphones connected to HEADPHONE (J1301)? ••• Disconnect them.
3) Is ANT-CABLE disconnected or connected improperly? ••• Connect it correctly as per the operation manual.
Refer to "No sound output in all modes".
Is the SIF signal (SIF_IN+) sent to pin (31) of IC3002 (VCT)?
Is the audio signal (SIF) sent from pin (1) of CONNECTOR
(SC2705)?
(TUNER)
Is the audio signal (SIF) sent from pin (12) of IC201 (IF-
DEMOD)?
(TUNER)
Is the SIF signal sent to pins (23) and (24) of IC201 (IF-
DEMOD)?
(TUNER)
Is the IF signal sent from pin (17) of TUNER (TU201)?
Check whether 5V (CONT) and 5V are supplied to pins (1) and
(2) of TUNER (TU201) respectively. Check SDA/SCL and AGC
signal.
No sound from speakers
YES
YES
YES
YES
No sound (during the reception of TV broadcasting)
NO
NO
NO
NO
NO
NO
NO
NO Check IC3002 or peripheral circuits.
NO Check SC2704 and P1201 or peripheral circuits. Is the S-MUTE
signal "L"?
NO Check HEAD-PHONE (J1301) or peripheral circuits.
NO Check P301 (AUDIO-CONNECTOR) and peripheral circuits.
YES Check whether +5V and +8V are supplied to pins (33) and (18) of
IC3002 respectively. Or, check peripheral circuits.
YES Check pin (31) of IC3002 (VCT) and peripheral circuits.
YES Check Q203 (AMP) and peripheral circuits.
YES Check IC201 and peripheral circuits.
YES Check FL202 and peripheral circuits.
YES Replace TUNER (TU201).
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