Sharp LC-20B6E (serv.man9) Service Manual ▷ View online
26
LC-20B6E
TROUBLE SHOOTING TABLE
No picture and no sound
Back light lamp failure to light up
Check all the settings microprocessor's adjust process menu.
Do F3701 and F3702 function?
Remove F3701 and F3702,
Replace F3701 and F3702.
Replace F6701.
Yes
No
and check the load sid
e
No
Yes
Is there short-circuiting?
Yes
Are T701's secondary outputs,
Is there short-circuiting of
Check S4053 and
Is the pin (178) of IC1201 in
Check the OFL1 line, IC1201
+35V, +9V and -12V
T701 primary side periphery,
No
connection cable.
the "H" state?
No
and their peripheral parts.
normal
?
Q709,Q711,Q716 and S4053?
Yes
No
Yes
Is T701's primary oscillator
Check J3701 periphery and
Are Q6705
윟
6712
Check Q6705
윟
6712
waveform normal?
connection cable.
short-circuiting?
No
and their peripheral parts.
Yes
Yes
Check T701's secondary
Is the primary side of
Check T6701
윟
T6712,
load.
T6701
윟
T6712 periphery
No
Q6705
윟
Q6712 and
short-circuitin
g?
connection cable
Yes
Replace the back light lamp
with new one and check
a
g
ain
.
27
LC-20B6E
No picture
(1/3)
No picture at all
No TV output
No VIDEO2 output
Check all the settings microprocessor's adjust process menu.
Is in/output of
Check IC801
Is voltages at
Check their
Is input at pin
Check V2_V line
IC801 normal?
No
and its
pins (3),(7) and (9
)
No
power lines.
(8) of IC3401
No
and its
Y
es
per
ip
h
era
l parts.
o
f tuner norma
l?
norma
l?
per
ip
h
era
l parts.
Ye
s
Is in/output of
Check IC1201
Is output at pin
Check tuner
IC1201 normal?
No
and its
(11) of tuner
No
and its
Y
es
per
ip
h
era
l parts.
norma
l?
per
ip
h
era
l parts.
Y
es
Check LCD
Is input at pin
Check its line.
pane
l vo
ltages
(4
7
) o
f
IC3401
N
o
an
d
wave
form.
norma
l?
Ye
s
Is output at pin
Check IC3401
(40) of IC3401
No
and its
normal?
peripheral parts.
Ye
s
Is output at pin
Check its line.
(216)
o
f
IC801
N
o
norma
l?
28
LC-20B6E
No picture
(2/3)
No S-VIDEO output
No VIDEO1 output
No COMP VIDEO output
No PC R/G/B output
No TELETEXT output
Check all the settings microprocessor's adjust process menu.
Is input at pins
Is input at pins (1)
Is input at pins
Check IC801
(10),(12) of IC3401
(3) of IC3401
(305),(301),(303) and
Yes
and its
normal?
normal?
(117) of IC801 normal?
peripheral parts.
No
No
Is the pin (1) o
f
Check the pin
No
IC403 in the
No
(48) of IC2001.
"H" state?
Check the V2_SY-line,
Check IC3401
Yes
Is output at pins (3),(5),
Check the R,G,B
V2_SC-line
and
their
and its
(7) and (10) of
Yes
and FB line.
peripheral parts.
peripheral parts.
Check IC403 and
IC1602 normal?
its per
ip
h
era
l parts.
N
o
Is output at pins
Check their lines
(57)
윟
(59) and (60) of
No
and its peripheral
IC1601 normal?
parts.
Is the pin (1) of
Check the pin
Ye
s
IC403 in the "L"
No
(48) of IC2001.
state?
Ye
s
Check IC1601 and
its peripheral parts.
Check IC403
and its peripheral
parts.
29
LC-20B6E
No picture
(3/3)
Colour is unusual
Gradation defect
Check all the settings microprocessor's adjust process menu.
Is output of
Check R1236,R1237
Is output V0,V31,V63,V95,V127,
Check IC1101
R0±
윟
R3±
No
and their
V159,V191 and V247 normal?
No
and its peripheral
norma
l?
per
ip
h
era
l parts.
parts.
Y
es
Is output of
Check R1238,R1239
G0±
윟
G3±
No
and their
norma
l?
per
ip
h
era
l parts.
Y
es
Is output of
Check R1240,R1241
B0±
윟
B3±
No
and their
norma
l?
per
ip
h
era
l parts.
Display
