Read Sharp LC-37HV4E (serv.man8) Service Manual online
25
LC-37HV4E
No sound comes out. (Connect to the AVC System and check.)
Is power supplied to each
IC in the audio unit?
IC in the audio unit?
Is an audio signal appearing
at pin (8) (L-IN) and pin (10)
(R-IN) of P3802?
at pin (8) (L-IN) and pin (10)
(R-IN) of P3802?
YES
Is an audio signal appearing
at pins (10) and (14) of
IC3812 (Audio Output)?
at pins (10) and (14) of
IC3812 (Audio Output)?
YES
YES
YES
YES
NO
Check around the
power regulator circuit
(IC3809, IC3810).
power regulator circuit
(IC3809, IC3810).
NO
Is an audio signal
appearing at pins (13)
and (20) of SC2202 in
the main unit?
appearing at pins (13)
and (20) of SC2202 in
the main unit?
NO
NO
Are Q3812 and Q 3813
(MUTE Circuits)
operating?
(MUTE Circuits)
operating?
Is an audio signal appearing
at pins (24), (27), (28) and
(31) of IC3812 (Audio
Output)?
at pins (24), (27), (28) and
(31) of IC3812 (Audio
Output)?
YES
Check if RY3801 (for
Internal/External switching) is
operating properly.
Internal/External switching) is
operating properly.
NO
NO
Check D3828-D3831
for short-circuiting and
check the circuits
around IC3812.
for short-circuiting and
check the circuits
around IC3812.
NO
Check IC3801, IC3803,
IC3804-IC3807, and
IC3811 for I/O signals.
IC3804-IC3807, and
IC3811 for I/O signals.
Check around Q2012 and Q2014 and check the
wire connected between the main unit and
audio unit.
wire connected between the main unit and
audio unit.
The whole screen is whitish (LCD power supply)
Disconnect the FFC from CN4101,
CN4102 and CN4601-CN4604.
(Otherwise it may cause the panel to get
broken.)
CN4102 and CN4601-CN4604.
(Otherwise it may cause the panel to get
broken.)
Check the power supplies.
Check the power supplies to CN4101
and CN4102 in particular.
Check the power supplies to CN4101
and CN4102 in particular.
YES
Is the voltage of R4114 around 6V?
YES
Check the I/O voltages of IC4103,
IC4105 and IC4106.
IC4105 and IC4106.
Check the performance of Q4101
and Q4112 and check the
resistances around IC4102.
and Q4112 and check the
resistances around IC4102.
TROUBLE SHOOTING TABLE (Continued)
