Sharp LC-37D90U Service Manual page 82

LC-37D90U
COMPOSITE: No external input video
[INPUT-1]
Is INPUT-1 selected on the input select
menu screen? Is the INPUT-SELECT for
the input signal?
YES
Select INPUT-1 on the input
select menu screen for the
right input signal.
Does the INPUT-1
V1.PLUG detection func-
tion?
Check the line between pin
(5) of input terminal (J501)
and pin (70) of IC501
(AV_SWITCH).
Is there the COMPOSITE video signal input
at pin (65) of IC501 (AV_SWITCH)?
Check the line between pin
(4) of J501 and pin (65) of
IC501.
YES
[COMPOSITE signal input] Is there the COMPOSITE video signal output at pin (60) of IC501?
[S-VIDEO signal input] Is there the video signal output at pins (60)(Y) and (59)(C) of IC501?
[COMPOSITE signal input] Is there the COMPOSITE video signal output at pin (2) of connector (SC501) on the
IF unit?
[S-VIDEO signal input] Is there the video signal output at pins (2)(Y) and (4)(C) of connector (SC501) on the IF
unit?
[COMPOSITE signal input] Is there the COMPOSITE video signal input at pin (2) of connector (SC1101) on the
main unit?
[S-VIDEO signal input] Is there the video signal input at pins (2)(Y) and (4)(C) of connector (SC1101) on the
main unit?
COMPOSITE: No external input video
Is INPUT-2 selected on the input select
menu screen with the S terminal open?
YES
NO
Is there the COMPOSITE video signal
input at pin (3) of IC501 (AV_SWITCH)?
NO
YES
YES
YES
No video (1)
[INPUT-2]
Is INPUT-2 selected on the input select menu
screen?
NO
Select INPUT-2 on the
input select menu
screen.
Does the INPUT-2
V3.PLUG detection func-
tion?
Check the line between
pin (2) of input terminal
(J501) and pin (2) of
IC501 (AV_SWITCH).
Is there the S-VIDEO signal input at pins (5)(Y)
and (7)(C) of IC501 (AV_SWITCH)?
NO
Check the line between
pin (1) of J501 and pin
(3) of IC501.
6 – 3
S-VIDEO: No external input video [INPUT-2]
YES
Select INPUT-2 on the input
select menu screen.
Does the INPUT-2 S3.PLUG
detection function?
Check the line between pin (6) of
input terminal (J503) and pin (6)
of IC501 (AV_SWITCH).
Check the line between pins
(3)(Y)/(4)(C) of J503 and pins
(5)/(7) of J501.
YES
Check IC501 and
its peripheral cir-
cuits.
NO
Check the line
between IC501 and
SC501 (Q501 thru
NO
Q504, etc.).
Check the SC501
and SC1101 con-
nectors.
NO
NO
NO