Sharp LC-28HM2, Service Manual

Page: 42 / 128

42
LC-28HM2
AN-28SP2
TROUBLE SHOOTING TABLE
(Continued)
No po
wer suppl
y
Chec
k LED lamp color
.
Displa
y - Green,
A
VC system - Green
(Nor
mal)
Displa
y - Green,
A
VC system - Red
(F
aulty condition)
Press po
w
er
b
utton of remote
controller
.
Chec
k po
w
er
supply at A
VC
system.
Displa
y - Red, A
VC
system - Green (F
aulty condition)
Press po
w
er
b
utton of remote
controller
.
Switch off the po
w
er
.
Chec
k IC2004.
Displa
y - Red, A
VC
system - Red (Same as stand-b
y
Press po
w
er
b
utton of remote
controller
.
Star
t up with the
displa
y process
adjustment mode
.
Chec
k po
w
er and
GND of IC2004.
Chec
k pins (5)
and (6) of IC2004.
Is pin (19) (MPO
W)
of IC2004 at high le
v
el?
Chec
k lamp
condition. Is there an
y brok
en
lamp?
If it is lik
ely that
lamp error count is tr
igger
ing alar
m,
reset the lamp error counter
.
Chec
k CCKM line
per
ipher
als of both
displa
y and center
.
Chec
k the system
cab
le
.
Displa
y LED is
OFF
.
Is +5V a
v
ailab
le at
pin (5) of P2001?
Is +5V a
v
ailab
le at
pin (2) of P3601 on RC unit?
Chec
k LED and
per
ipher
als on RC
unit.
Chec
k RC PWB
fur
nace or +5V
po
w
er line
.
A
VC system LED is
OFF
.
Is there LED
VCC
output from monitor?
Chec
k LED per
ipher
als on front
ter
minal unit.
Is +5V a
v
ailab
le at pin (37) of SC404 and
pin (13) of both D501 and SC401?
No
No
Is specified v
oltage
output a
v
ailab
le
from displa
y po
w
er
unit?
Ye
s
Is pin (19) (MPO
W)
of IC2004 at high le
v
el?
Ye
s
Is specified v
oltage
output a
v
ailab
le
from DC/DC unit?
Ye
s
Chec
k the
per
ipher
al circuits
of X2001.
No signal
Chec
k the
per
ipher
al circuits
of IC2004.
No
No
Ye
s
Ye
s
Ye
s
Ye
s
No
Change occurs
.
No change occurs
.
No change occurs
.
No screen appears
.
No screen appears
.
No prob
lem
Signal present
The set star
ts up
.
Screen appears once
,
b
ut disappears
soon.
When CCKM per
ipher
als are
not f
aulty
.
<Ref
erence>
DC/DC PWB output
+3.3V
, +5V
, -4.5V
,
-15V
, +28V
, +9V
Displa
y po
w
er unit output
+13V
, 5V
Chec
k DC/DC unit.
No
Chec
k displa
y
po
w
er unit.
If A
C po
w
er connection is nor
mal, it is
possib
le that displa
y po
w
er unit is
faulty
.
It is also possib
le that +5V line is shor
t-
circuited and activ
ating the protection
circuit f
or the displa
y po
w
er unit.