Sharp LC-20B2H, Service Manual

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14
LC-20B2H
LC-20B2M
TROUBLE SHOOTING TABLE
(Continued)
No picture and sound
No color
No TV color
No S-VIDEO color
Yes
No
Do F3701, F3702, F3703 and F3704 function?
Check all the settings on the microprocessor
’s
adjust process menu.
No
Are secondary outputs (+38V
, +16V
, +9V
, +5V
, -8V)
of
T3701 as specified?
Yes
Are the oscillation waveform at
T3701’
s primary side as
specified?
Yes
No
Disconnect F3701, F3702, F3703 and F3704. Is the load side short-circuited?
Yes
No
Is any of
T3701’
s primary
side, Q3700 and S4701 short- circuited?
Check J3701, its peripheral parts and connection cable.
Replace F3701, F3702, F3703 and F3704.
Check S4701 and connection cable.
Check the secondary-side load of
T3701.
Fluorescent lamp
Yes
No
Does F3703 and F3704 function?
Yes
No
Is Pin (34) of IC1201 at “H”?
Yes
No
Are the oscillation waveforms at the primary side of
T6551-3
and
T6751-3 as specified?
Yes
Replace F3703 and F3704.
No
Is input at Pin (71) of IC801 as specified?
Check P5001, SC line and peripheral parts.
Yes
Check the line, IC1201 and its peripheral parts.
Check Q6551-2, Q6555, Q6751-2, Q6755,
T6551-3,
T6751-3 and their peripheral parts.
Replace the fluorescent lamp and check the oscillation waveform again.
No VIDEO color
Check all the settings on the microprocessor
’s
adjust process menu.
No COMPONENT color
No
Is input at Pins (4) and (6) of IC801 as specified?
Check J3405, J3406, PB line, PR line and peripheral parts.