Sharp AQUOS LC-20B5M, Service Manual

Page: 26 / 91

26
LC-20B5M
TROUBLE SHOOTING TABLE
(Continued)
No sound
No sound fr
om speaker
s
YES YES YES YES YES YES
NO
YES YES YES YES
NO NO NO NO NO
NO NO NO NO
Chec
k the f
ollo
wing.
1
No audio output from
TV ...
Chec
k the
per
ipher
al circuits of Q3202 and
TU3000.
2
No audio output from
VIDEO 1 input ...
Chec
k J3402 thr
u pins (2) and (4) of
IC3401.
3
No audio output from
VIDEO 2 input ...
Chec
k J3409 thr
u pins (22) and (24) of
IC3401.
4
No audio output from
VIDEO 3 input ...
Chec
k J3403 thr
u pins (9) and (11) of
IC3401.
5
No audio output from COMPONENT input ...
Chec
k J3406 and J3404 thr
u pins (46) and
(48) of IC3401.
Is there the audio output in an
y input mode (TV
,
VIDEO 1/2
and COMPONENT)? Chec
k the f
ollo
wing.
1
Is the monitor output setting at "A
udio fix
ed"?
2
Is the sound v
olume loud enough?
3
Is the m
ute mode released?
4
Are the headphones unplugged?
Is the po
w
er supply v
oltage at each circuit nor
mal?
Pin (8) of IC3301 and pin (39) of IC3201
Appro
x.
+8V
Pins (11), (12), (13), (65) and (66) of IC3201 Appro
x.
+5V
No sound fr
om monitor output
Is there the audio signal output at pins (33)(Rch) and (34)(Lch) of IC3201? Is pin (58) of IC2001 "H"? Is the signal from the Q2203 collector "L"? Chec
k pins (33)(Rch) and (34)(Lch) of IC3201 thr
u pins
(4)(Lch) and (2)(Rch) of J3404.
Chec
k the f
ollo
wing.
1
Is there the audio output from speak
ers?
2
Is the monitor output connected correctly?
3
Is the m
ute mode released?
Chec
k the f
ollo
wing.
1
Go to "No A
udio from Speak
ers"h.
2
Connect the monitor output correctly
.
3
Release the m
ute mode
.
Chec
k the per
ipher
al circuits of IC3201.
Chec
k pin (4) of J4021 thr
u pin (58) of
IC2001. Chec
k pin (55) of IC2001 thr
u Q2203, and
Q2201.
Is there the control signal input at each pin of IC3201?
Pin (2) of IC3201 SCL1 Pin (3) of IC3201 SD
A1
Are the oscillation w
a
ves from pins (71) and (72) of IC3201
nor
mal?
Chec
k pins (29) and (30) of IC2001 thr
u pins (2)
and (3) of IC3201. Chec
k the per
ipher
al circuits of X3201.
Is there the audio signal output at pins (27)(Rch) and (28)(Lch) of IC3201? Chec
k pins (27)(Rch) and (28)(Lch) of IC3201 thr
u pins
(7)(Rch) and (1)(Lch) of IC3301, and the per
ipher
al circuits
of IC3301 and IC3303.
Chec
k the per
ipher
al circuits of IC3201.
Rechec
k the f
ollo
wing.
1
Set the monitor output to "A
udio fix
ed".
2
Increase the sound v
olume
.
3
Release the m
ute mode
.
4
Unplug the headphones
.
Chec
k the f
ollo
wing.
+8V system ...
Chec
k the per
ipher
al circuits of
Q3711 thr
u pin (8) of IC3301 and
pin (39) of IC3201.
+5V system ...
Chec
k the
T701 output B5V500MA
line thr
u each +5V input pin of
IC3201.