Read Sharp LC-20S1E (serv.man8) Service Manual online
16
LC-20S1E
TROUBLE SHOOTING TABLE
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.
17
LC-20S1E
TROUBLE SHOOTING TABLE
(Continued)
No picture (1/3)
Check all the settings microprocessor
’s adjust process menu.
Is in/output of
IC801 normal?
Is in/output of
IC1201 normal?
Check IC801
and its
peripheral parts.
Check IC1201
and its
peripheral parts.
Check LCD
panel voltages
and waveform.
Yes
Yes
No
No
No picture
at all
Is voltages at
pins (6), (7) and
(18) of tuner
normal?
Is output at pin
(13) of tuner
normal?
Check the
power line.
Check tuner
and its
peripheral parts.
Is input at pin
(16) of IC802
normal?
Is the pin (3)
of IC802 at "H"
state?
Yes
Yes
No
No
No
No
No
Yes
No TV output
Is the pin (48)
of IC2001 at
"H" state?
Yes
Check the its
line.
Check the its
line.
Check IC802
and its
peripheral parts.
Is input at pin
(7) of IC802
normal?
Check V1_V
line and its
peripheral parts.
No
No VIDEO 2
output
18
LC-20S1E
TROUBLE SHOOTING TABLE
(Continued)
No picture (2/3)
Check all the settings microprocessor
’s adjust process menu.
Is input at pin
(14) of IC802
normal?
Check the V2_V
line and its
peripheral parts.
No
No VIDEO 1
output
Check the SY-line,
SC-line and their
peripheral parts.
Is input at pin (9)
of IC802 and pin
(1) of IC805
normal?
No
No S-VIDEO
output
Check IC1201
and its
peripheral parts.
No
Yes
Yes
No TELETEXT
output
Is input at pins (136),
(137), (138), and
(142) of IC1201
normal?
No
Check the R, G
and B line.
Is output at pins
(57)~(59) of IC1601
normal?
No
Yes
Check Vout line and
its peripheral parts.
Is input at pin (21) of
IC1601 normal?
Check IC1601 and its
peripheral parts.
19
LC-20S1E
TROUBLE SHOOTING TABLE
(Continued)
No picture (3/3)
Check all the settings microprocessor
’s adjust process menu.
Is output of
R0~R7
normal?
Is output of
G0~G7
normal?
Is output of
B0~B7
normal?
Yes
Yes
No
No
No
Colour is
unusual
Is in/output of
SPIO and
SPOI normal?
No
No picture
image
inversion
No
Gradation
defect
Is output of U/D
normal?
Yes
No
Check R1224, R1227
and their peripheral
parts.
Check R1234 and
its peripheral parts.
Check IC1202, Q1206
and their peripheral
parts.
Check R1231, R1267
and their peripheral
parts.
Check R1268, R1269
and their peripheral
parts.
Is output V0, V7, V21,
V64, V112, V176,
V235 and V255
normal?
Check IC1101 and its
peripheral parts.