Sharp AQUOS LC-20S1E, Service Manual

Page: 16 / 78

16
LC-20S1E
TR
OUBLE SHOO
TING
T
ABLE
No picture and No sound
Check all the settings microprocessor’s adjust process menu.
Do F3301 and F3302
function?
Are T3701’s secondary
outputs, +34V, +9V, +5V
and -110V normal?
Replace F3301 and F3302.
Check S4001 and
connection cable.
Is T3701’s primary oscillator
waveform normal?
Check T3701’s secondary
load.
Yes Yes
No No
No No
No
Yes
Check J3300 periphery and
connection cable.
Replace F6700~F6704.
Yes
Yes
No
No
No
Yes
Yes
Check the OFL line, Q3600,
Q3601 and their peripheral
parts.
Check T6700~T6704,
Q6700~Q6705 and
connection cable.
Back light lamp failure to light up
Is the primary side of
T6700 ~T6704 periphery
short-circuiting?
Replace the back light lamp
with new one and check
again.
Remove F3301 and F3302
and check the load side.
Is there short-circuiting?
Is there short-circuiting of
T3701 primary side periphery,
Q3701, Q3703 and S4001.
Are the pins (120) and (121)
of IC1201 in the "H" state?
Are the outputs of Q3600 and
Q3601 in the "L" state?
Check the OFL1 line, OFL2
line, IC1201 and their
peripheral parts.