Read Sharp LC-37RD2E (serv.man5) Service Manual online
LC-32RD2E/RU, LC-37RD2E/RU
4 – 2
No sound from speakers
No sound output in all modes.
Is the audio signal properly sent from pins (28) (L-ch) and (27)
(R-ch) of IC3001?
NO
Check IC3001 or peripheral circuits.
YES
Is the audio signal of pins (3) (L-ch) and (5) (R-ch) of IC303 (OP-
AMP) sent properly?
AMP) sent properly?
NO
Check SC2704 and P1201 or peripheral circuits. Is the S-MUTE
signal “L”?
signal “L”?
YES
Is the audio signal of pin (4) of IC301 (R-ch)/IC302 (L-ch)
(AUDIO-AMP) sent properly?
(AUDIO-AMP) sent properly?
NO
Check HEAD-PHONE (J1301) or peripheral circuits.
YES
Is the audio signal output of pins (2, 1) (L-ch) and (4, 3) (R-ch) of
P301 (AUDIO-CONNECTOR) normal?
P301 (AUDIO-CONNECTOR) normal?
NO
Check P301 (AUDIO-CONNECTOR) and peripheral circuits.
YES
Check Speaker Box (right and left) and wire harness.
No sound (during the reception of TV broadcasting)
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.
NO
Refer to “No sound output in all modes”.
NO
Is the SIF signal (SIF_IN+) sent to pin (31) of IC3001 (VCT)?
YES
Check whether +5V and +8V are supplied to pins (33) and (18) of
IC3001 respectively. Or, check peripheral circuits.
IC3001 respectively. Or, check peripheral circuits.
NO
Is the audio signal (SIF) sent from pin (1) of CONNECTOR
(SC2742)?
(SC2742)?
YES
Check pin (31) of IC3001 (VCT) and peripheral circuits.
(TUNER)
NO
Is the audio signal (SIF) sent from pin (12) of IC201 (IF-
DEMOD)?
DEMOD)?
YES
Check Q203 (AMP) and peripheral circuits.
(TUNER)
NO
Is the SIF signal sent to pins (23) and (24) of IC201 (IF-
DEMOD)?
DEMOD)?
YES
Check IC201 and peripheral circuits.
(TUNER)
NO
Is the IF signal sent from pin (17) of TUNER (TU201)?
YES
Check FL202 and peripheral circuits.
NO
Check whether 5V (CONT) and 5V are supplied to pins (1) and
(2) of TUNER (TU201) respectively. Check SDA/SCL and AGC
signal.
(2) of TUNER (TU201) respectively. Check SDA/SCL and AGC
signal.
YES
Replace TUNER (TU201).
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