LG 47LG50DC (CHASSIS:LA85Z) Service Manual ▷ View online
C
2008
- 17 -
TROUBLESHOOTING
1. TV/CA
TV
-VIDEO
Check T
U
1 Pin16(Vid
eo outp
u
t)
Can you see the normal signa
l?
Check the input(Pin1) of LPF(IC808).
Can
you se
e the normal
w
a
vef
orm?
YES
NO
Coul
d
you mea
sure voltag
e of T
U
1 & IIC lines?
Are they
a
ll nor
mal?
Check the outp
ut(Pin8) of LPF
(IC808).
Can
you se
e the normal
w
a
vef
orm?
Check the input(PinAN16) of BCM3553(IC100).
Measure
w
a
vef
orm at C658 because itís mor
e eas
y
to ch
ec
k.
Can
you se
e the normal
w
a
vef
orm?
NO
You should check po
w
e
r l
ine
& IIC lines.
YES
You shou
ld rep
lace T
UNER.
NO
After checking video signal line & the Pow
e
r of LPF you sho
uld dec
ide to r
eplac
e item or not.
NO
After checking the Po
w
e
r of LPF you should
decide to replace LPF
or not.
NO
T
h
is board has big problem because Main c
h
ip(BCM3553) have some troubles.
After checking
thoroug
hl
y al
l p
a
th once ag
ain
,
You should d
e
cide
to rep
lac
e
BCM355
3 or not.
YES
YES
Check all po
w
e
r domain of FR
C-9459M (IC1000)
(3.3V, 1.3V_CORE,1.3V_PLL,3.3V,1.8V,2.5V)
& cry
stal output (X
1000 / 20.25MHz)&FRC_RESET
Measure Po
w
e
r &
w
a
veform a
t L1008,L1
007,
L100
2,L10
13,
L1014,L1015~
L1018&C1006&R1029
becaus
e itís more eas
y to check.
Can
you se
e the normal
w
a
vef
orm?
YES
T
h
is board has
big prob
lem b
e
cause F
RC c
h
ip(F
RC-
945
9
M) have some
troubles.
After checking
thoroug
hl
y al
l p
a
th once ag
ain
, You should d
e
cide
to rep
lac
e
FRC-945
9M.
Althoug
h
you r
eplac
e it,
y
ou c
annot see n
o
rm
al disp
la
y, de
cide to repl
ace
M
a
in
ch
ip
(B
C
M
3553
)
YES
C
2008
- 18 -
2. A
V
-VIDEO
Check JK701, JK707
Can
you se
e the normal
w
a
vef
orm?
NO
JK701,JK707 ma
y
h
a
ve problem. Repl
ace this Jack.
Check the in
put (Pin AN17,AM19) of BCM3
553(IC100).
Measure
w
a
vef
orm at C651,C
652 bec
ause ití
s more eas
y
to
check.
Can
you se
e the normal
w
a
vef
orm?
YES
NO
T
h
is board has big problem because Main c
h
ip(BCM3553) have some troubles.
After checking
thoroug
hl
y al
l p
a
th once ag
ain
,
You should d
e
cide
to rep
lac
e
BCM355
3 or not.
Check all po
w
e
r domain of FR
C-9459M (IC1000)
(3.3V, 1.3V_CORE,1.3V_PLL,3.3V,1.8V,2.5V)
& cry
stal output (X
1000 / 20.25MHz)&FRC_RESET
Measure Po
w
e
r &
w
a
veform a
t L1008,L1
007,
L100
2,L10
13,
L1014,L1015~
L1018&C1006&R1029
becaus
e itís more eas
y to check.
Can
you se
e the normal
w
a
vef
orm?
YES
T
h
is board has
big prob
lem b
e
cause F
RC c
h
ip(F
RC-
945
9
M) have some
troubles.
After checking
thoroug
hl
y al
l p
a
th once ag
ain
, You should d
e
cide
to rep
lac
e
FRC-945
9M.
Althoug
h
you r
eplac
e it,
y
ou c
annot see n
o
rm
al disp
la
y, de
cide to repl
ace
M
a
in
ch
ip
(B
C
M
3553
)
YES
C
2008
- 19 -
3. COMPONENT
-VIDEO
Check JK700,JK702.
Can
you se
e the normal
w
a
vef
orm?
JK700,JK702 ma
y
h
a
ve problem. Repl
ace this Jack.
Check the in
pu
t (Pin AL21,AM21,AN21 a
nd P
inAN2
2,AL22,
AP22)
of BCM3553(I
C100).
Measure
w
a
vef
orm at C638,C
639,C640 and C628,C629,C
6
3
0
because itís more eas
y to check.
Can
you se
e the normal
w
a
vef
orm?
YES
NO
NO
T
h
is board has big problem because Main c
h
ip(BCM3553) have some troubles.
After checking
thoroug
hl
y al
l p
a
th once ag
ain
,
You should d
e
cide
to rep
lac
e
BCM355
3 or not.
Check all po
w
e
r domain of FR
C-9459M (IC1000)
(3.3V, 1.3V_CORE,1.3V_PLL,3.3V,1.8V,2.5V)
& cry
stal output (X
1000 / 20.25MHz)&FRC_RESET
Measure Po
w
e
r &
w
a
veform a
t L1008,L1
007,
L100
2,L10
13,
L1014,L1015~
L1018&C1006&R1029
becaus
e itís more eas
y to check.
Can
you se
e the normal
w
a
vef
orm?
YES
T
h
is board has
big prob
lem b
e
cause F
RC c
h
ip(F
RC-
945
9
M) have some
troubles.
After checking
thoroug
hl
y al
l p
a
th once ag
ain
, You should d
e
cide
to rep
lac
e
FRC-945
9M.
Althoug
h
you r
eplac
e it,
y
ou c
annot see n
o
rm
al disp
la
y, de
cide to repl
ace
M
a
in
ch
ip
(B
C
M
3553
)
YES
C
2008
- 20 -
4. RGB-VIDEO
Check JK70
5.
Can
you se
e the normal
w
a
vef
orm?
YES
JK705 may have problem. Replace this Jack.
NO
Check the input (Pin AK16,AN15,AM15,AH16,AJ16)
of BCM355
x(I
C100).
Measure
w
a
vef
orm at C635,C
636,C637 and R755,R758
because itís more eas
y to check.
Can
you se
e the normal
w
a
vef
orm?
NO
T
h
is board has big problem because Main c
h
ip(BCM3553) have some troubles.
After checking
thoroug
hl
y al
l p
a
th once ag
ain
,
You should d
e
cide
to rep
lac
e
BCM355
3 or not.
Check all po
w
e
r domain of FR
C-9459M (IC1000)
(3.3V, 1.3V_CORE,1.3V_PLL,3.3V,1.8V,2.5V)
& cry
stal output (X
1000 / 20.25MHz)&FRC_RESET
Measure Po
w
e
r &
w
a
veform a
t L1008,L1
007,
L100
2,L10
13,
L1014,L1015~
L1018&C1006&R1029
becaus
e itís more eas
y to check.
Can
you se
e the normal
w
a
vef
orm?
YES
T
h
is board has
big prob
lem b
e
cause F
RC c
h
ip(F
RC-
945
9
M) have some
troubles.
After checking
thoroug
hl
y al
l p
a
th once ag
ain
, You should d
e
cide
to rep
lac
e
FRC-945
9M.
Althoug
h
you r
eplac
e it,
y
ou c
annot see n
o
rm
al disp
la
y, de
cide to repl
ace
M
a
in
ch
ip
(B
C
M
3553
)
YES
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