Service manual

39
LC-20B4U-S
LC-20B4U-B
TROUBLE SHOOTING TABLE (Continued)
Check all the settings on the microprocessor
’s adjust process menu.
No picture
No picture
at all
Yes
No
Check
IC3401 and
its peripheral
parts.
Check
IC1201, its
peripheral
circuits and
the LCD
panel.
Check IC806
and its
peripheral
circuits.
Yes
No
No
No VIDEO
1 or 2
output
Yes
No
Are inputs
and outputs
of IC3401 as
specified?
Check
IC3401 and
its peripheral
parts.
Check
IC8201 and
its peripheral
parts.
No
Is input at
Pin (73) of
IC806 as
specified?
Check IC806,
AV1 line and
their
peripheral
parts.
Yes
No
Are input and
output of
IC8201 as
specified?
Check
IC3401 and
its peripheral
parts.
Yes
No
Are input and
output of
IC3401 as
specified?
No
Are pin
(67) of
IC2001
at “H”?
No S
VIDEO
output
Yes
Yes
Yes
Yes
Are pins (3),
(8) and (9) of
IC3401 “L”,
“H”and “L”?
No
No
No
Are inputs at
Pins (72) and
(73) of IC806
as specified?
Check
SC3405, SY
line, SC line
and peripheral
parts.
No
COMPONENT
output
No
Is input at
Pins (1), (2),
(3) and (75)
of IC806 as
specified?
Check J3404,
DVD-Y line,
PB line, PR
line and
peripheral
parts.
No TV
output
Yes
No
Are voltages
at Pins (6),
(7) and (9) of
tuner as
specified?
Check the
power line.
Yes
No
Is output at
Pin (19) of
tuner as
specified?
Check the
tuner and
its
peripheral
No
Is input at Pin
(16) of
IC3401
as specified?
Check the
line in
question.
Yes
Check
IC3401 and
its peripheral
parts.
Yes
No
Are Pins (3)
of IC3401 at
“H”
respectively?
Are Pins
(48) IC2001
at “H”
respectively
?
Yes
Check the
line in
question.
Check pin
(88) of
IC2001 or
the SSW
line.
Are inputs
and outputs
of IC806 as
specified?
Does the LCD
controller test
pattern
appear?
Does the
video decoder
test pattern
appear?
No
Is input at Pins
(131), (132)
and (133) of
IC1201 as
specified?
No
No
Check P1201
YP line, CPB
line and
peripheral
parts.
Check C1275
Check J3404, DVD-Y line,
PB line, PR line and
peripheral parts.
Check
QCNW-
B233WJZZ
Is input at Pin
(26) of IC1203
as specified?
Is an error
message
displayed?
Is the
progressive
input
coming?
Progressive
input "No"
Progressive
input "Yes"
Out-of-support
message "Yes"