Read Sharp LC-37SD1E (serv.man4) Service Manual online
LC-37SD1E/RU
4 – 2
No sound (1) (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.
Is the audio signal (L/R)
sent from pins (28) and
(27) of IC3002 (VCT)?
NO
Is the SIF signal (SIF_IN+)
sent to pin (31) of IC3002
(VCT)?
sent to pin (31) of IC3002
(VCT)?
YES
Check whether +5V and
+8V are supplied to pins
(33) and (18) of IC3002
respectively. Or, check
peripheral circuits.
+8V are supplied to pins
(33) and (18) of IC3002
respectively. Or, check
peripheral circuits.
(AV-UNIT)
YES
NO
Is the audio signal of pins
(3) and (5) of IC303
(OP-AMP) sent properly?
(3) and (5) of IC303
(OP-AMP) sent properly?
NO
Check SC2704 and P1201
or peripheral circuits.
Is the S-MUTE signal “L”?
or peripheral circuits.
Is the S-MUTE signal “L”?
Is the audio signal (SIF)
sent from pin (1) of
CONNECTOR (SC2705)?
sent from pin (1) of
CONNECTOR (SC2705)?
YES
Check pin (31) of IC3002
(VCT) and peripheral
circuits.
(VCT) and peripheral
circuits.
YES
(TUNER) NO
Is the audio signal of pin
(4) of IC301/IC302
(AUDIO-AMP) sent
properly?
(4) of IC301/IC302
(AUDIO-AMP) sent
properly?
NO
Check HEAD-PHONE
(J1301) or peripheral
circuits.
(J1301) or peripheral
circuits.
Is the audio signal (SIF)
sent from pin (12) of IC201
(IF-DEMOD)?
sent from pin (12) of IC201
(IF-DEMOD)?
YES
Check connector (P201/
SC2705) and peripheral
circuits.
SC2705) and peripheral
circuits.
YES
NO
Is the audio signal output
of pins (2) and (4) of P301
(AUDIO-CONNECTOR)
normal?
of pins (2) and (4) of P301
(AUDIO-CONNECTOR)
normal?
NO
Check P301 (AUDIO-
CONNECTOR) and
peripheral circuits.
CONNECTOR) and
peripheral circuits.
Is the SIF signal sent to
pins (23) and (24) of IC201
(IF-DEMOD)?
pins (23) and (24) of IC201
(IF-DEMOD)?
YES
Check IC201 and
peripheral circuits.
peripheral circuits.
YES
NO
Check Speaker (right and
left) and wire harness.
left) and wire harness.
Is the IF signal sent from
pin (8) of TUNER
(TU201)?
pin (8) of TUNER
(TU201)?
YES
Check FL202 and
peripheral circuits.
peripheral circuits.
NO
Check whether 5V (CONT)
and 5V are supplied to
pins (1) and (7) of TUNER
(TU201) respectively.
Check SDA/SCL and AGC
signal.
and 5V are supplied to
pins (1) and (7) of TUNER
(TU201) respectively.
Check SDA/SCL and AGC
signal.
YES
Replace TUNER (TU201).
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