Sharp Aquos LC-20B4M, Service Manual

Page: 21 / 82

21
LC-20B4M
TROUBLE SHOOTING TABLE
(Continued)
Is Pin (53) of IC2001 at
“L
”?
Chec
k all the settings on the microprocessor
’s adjust process men
u.
Are outputs at Pins (1) and (7) of IC3301/ IC3303 as specified?
Are inputs at Pins (2) and (4) as w
ell as
outputs at Pins (8) and (12), all of IC3305, as specified?
Muting eff
ect is
on.
Chec
k the
FSMUTE line
.
Chec
k IC3301,
IC3303 and their per
ipher
al
par
ts
.
Are input and output of IC3304 as specified?
Chec
k IC3304
and its per
ipher
al par
ts
.
Chec
k the line
in question, IC3301 and its per
ipher
al
par
ts
.
Chec
k the
speak
ers and
their per
ipher
al
par
ts
.
Is Pin (55) of IC2001 at
“L
”?
Chec
k the
headphone and its per
ipher
al
par
ts
.
Chec
k Q2004,
J3303 har
ness
and their per
ipher
al par
ts
.
Is Pin (58) of IC2001 at
“L
”?
Are outputs at Pins (14) and (15) of IC3501 as specified?
Chec
k the line
in question.
Chec
k the
LMUTE line
.
Chec
k IC3501,
IC3304 and its per
ipher
al
par
ts
.
Is output at Pins (15) and (16) of tuner as specified?
Is input at Pin (67) of IC3304 as specified?
Chec
k IC3304,
X3301 and their per
ipher
al
par
ts
.
Chec
k the
tuner and its per
ipher
al
par
ts
.
Chec
k Q3201,
Q3202 and their per
ipher
al
par
ts
.
No sound fr
om
speaker
s
No sound
No sound fr
om
headphone
No sound fr
om output
line
TV sound failure
Yes
No No
Yes
No
Yes
No
Yes
Yes
No
Yes
No No
Yes
Yes
No No
Yes