Sharp LC-65D90U, Service Manual

Page: 42 / 167

42
LC-65D90U
TROUBLE SHOOTING TABLE
(Continued)
YES
YES
YES
YES YES YES YES YES YES
NO NO
NO
YES YES
NO
NO
NO
NO NO NO NO NO NO
At the input of <component video signal>
No picture comes out (3)
No e
xter
nal line input <INPUT
-1>
Is INPUT
-1 selected on the input select
men
u screen?
Select INPUT
-1 on the input select men
u
screen to ha
v
e
a desired input signal.
If the INPUT
-1 char
acters on the men
u
screen are g
ra
y and impossib
le to select:
See if the component video signal detection function w
o
rk
s
. Chec
k the line betw
een pin
(11) of J1107, pin (38) of IC3800 (A
V
SWITCH) and pin (78) of IC2501 (MUL
TI
SOUND PR
OCESSOR).
Is the component video signal inputted to pins (21), (23) and (25) (Y
, PB
, PR) of
IC3800 (A
V SWITCH)?
Chec
k the line betw
een the input pins from
J1107 to IC3801.
Are the
Y
, PB and PR signals outputted to pins (60), (59) and (58), respectiv
ely
, of IC3800?
No e
xter
nal line input <INPUT
-2>
Is INPUT
-2 selected on the input select
men
u screen?
Select INPUT
-2 on the input select men
u
screen to ha
v
e
a desired input signal.
If the INPUT
-2 char
acters on the men
u
screen are g
ra
y and impossib
le to select:
See if the component video signal detection function w
o
rk
s
. Chec
k the line betw
een pin
(10) of J1107 and pin (40) of IC3800 (A
V
SWITCH).
Is the component video signal inputted to pins (27), (29) and (31) (Y
, PB
, PR) of
IC3800 (A
V SWITCH)?
Chec
k the line betw
een the input pins from
J1107 to IC3801.
Chec
k IC3800 (A
V SWITCH) and its
per
ipher
al circuits
.
Chec
k the line betw
een IC3800 and
IC3807.
(Q3807, Q3806, Q3805, etc.)
Mak
e sure that the control signal is f
ed to
pins (3) and (22) of IC3807.
Is the
Y signal outputted to pin (20) of IC3807 (MUL
TIPLEXER)?
Is the Cb signal outputted to pin (18) of IC3807 (MUL
TIPLEXER)?
Is the Cr signal outputted to pin (16) of IC3807 (MUL
TIPLEXER)?
Is the
Y signal inputted to pin (1) of IC3807 (MUL
TIPLEXER)?
Is the Cb signal inputted to pin (5) of IC3807 (MUL
TIPLEXER)?
Is the Cr signal inputted to pin (3) of IC3807 (MUL
TIPLEXER)?
Chec
k the line betw
een IC3807 and P5404.
(Q3803, Q3808, Q3802, Q3809, Q3801, Q3810, etc.) Chec
k the B-to-B connector "PB".
Is the
Y signal inputted to pin (22) of the main unit's connector (PB_CN1800)?
Is the Cb signal inputted to pin (20) of the main unit's connector (PB_CN1800)? Is the Cr signal inputted to pin (18) of the main unit's connector (PB_CN1800)? Is the
Y signal outputted to pin (22) of the A
V
unit's connector (PB_P5404)?
Is the Cb signal outputted to pin (20) of the A
V
unit's connector (PB_P5404)?
Is the Cr signal outputted to pin (18) of the A
V
unit's connector (PB_P5404)?
Chec
k the line betw
een connector PB and
IC3702. Chec
k the
Y signal line betw
een pins (24) and (25) of IC3702 and pin (6) of IC3700.
Chec
k the Cb signal line betw
een pins (20) and (21) of IC3702 and pin (2) of IC3700.
Chec
k the Cr signal line betw
een pins (16) and (17) of IC3702 and pin (14) of IC3700.
Is the
Y signal inputted to pin (6) of IC3700 (ADC)?
Is the Cb signal inputted to pin (2) of IC3700 (ADC)? Is the Cr signal inputted to pin (14) of IC3700 (ADC)?
Chec
k IC3700 and its per
ipher
al circuits
.
Is the digital video signal outputted from the output ter
minals of IC3700?
Is the
Y signal inputted to pin (8) of IC3702 (L.P
.F
.)?
Is the Cb signal inputted to pin (11) of IC3702 (L.P
.F
.)?
Is the Cr signal inputted to pin (13) of IC3702 (L.P
.F
.)?