Sharp LC-37D90U Service Manual page 84

LC-37D90U
COMPONENT: 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 C1.PLUG
detection function?
Check the line between pin (8)
of input terminal (J501) and
pin (38) of IC501
(AV_SWITCH).
Is there the COMPONENT video signal
input at pins (21)(Y), (23)(Pb) and (25)(Pr)
of IC501 (AV_SWITCH)?
YES
Check the line between the
input terminals of J501 and
IC501.
Is there the COMPONENT video signal out-
put at pins (60)(Y), (59)(Pb) and (58)(Pr) of
IC501?
YES
Check IC501 and its periph-
eral circuits.
No video at UHF/VHF broadcast signal recep-
Is the specified TV signal selected on the input select menu screen?
NO
Is there the analog video signal output at the
output pin (4) of tuner (TU1101)?
YES
Check the tuner, IC8601 (DE-
MODULATOR) and their periph-
eral circuits (TUN_SDA/SCL,
Q8601).
Is there the video signal output at pin (5) of
IC1103 (LEVEL_ADJ)?
YES
NO
Does the level adjustment con-
trol signal come from pin (6) of
IC1103 to pin (1) of IC1104?
Check IC1104 and its peripheral
circuits. Replace as required.
Is there the CVBS3 signal input at pin (N3) of
IC3301 (VPC)?
NO
YES
No video (2)
tion
Is there the video signal output at the output pins
(20) and (21) of tuner (TU1101)?
NO
NO
Are there the MPEG signal outputs
(US_TS_PKTSYNC, US_TS_EN,
US_TS_DATA, US_TS_CLK) from IC8601?
NO
NO
Are there the MPEG signal inputs
(US_TS_PKTSYNC, US_TS_EN,
US_TS_DATA, US_TS_CLK) at IC8101 (CPU/
DECODER)?
NO
6 – 5
No video at digital broadcast signal reception
YES
Check the tuner, IC8601 (DE-MOD-
ULATOR) and their peripheral cir-
cuits (TUN_SDA/SCL, Q8601).
YES
Check IC8601 and its peripheral
control circuits.
YES
Check the line between IC8601 and
IC8101.
NO
NO
NO
NO