LG 42LC7D (CHASSIS:LA73E) Service Manual ▷ View online
- 41 -
- RGB_PC doesn't display
Check input c
onnect P7004.
Can y
o
u see t
h
e n
o
rmal
w
a
v
e
form?
Check the input of Component
s
w
itch(IC5002).
Can y
o
u see t
h
e n
o
rmal
w
a
v
e
form?
Check th
e o
u
tput o
f Co
mponent
s
w
itch(IC5002).
Can y
o
u see t
h
e n
o
rmal
w
a
v
e
form?
Check th
e in
put o
f MST
3361
(IC7004
Pin41,44,46).
Can y
o
u see t
h
e n
o
rmal
w
a
v
e
form?
YE
S
YE
S
YE
S
NO
P7004 may
h
a
v
e
problem. Replace this Jack.
Check the output of
MST3361(IC7004 ).
Can y
o
u see t
h
e n
o
rmal
w
a
v
e
form?
YE
S
Check th
e in
pu
t an
d
outpu
t of
BCM3550(IC4006). Especially
y
ou should
ch
eck
The
H,V sy
nc and clock.
Can y
o
u see t
h
e n
o
rmal
w
a
v
e
form?
YE
S
NO
A
fte
r checking the i
nput
TR
of RGBHV, y
ou
should decide
to replace these components or
not.
NO
NO
A
ft
e
r ch
ec
kin
g th
e Po
w
e
r of MST
3361
y
ou
should decide
to replace MST3361 or not.
NO
YE
X
This board ha
s big
problem
because Main
chip(BCM3
550)
hav
e some trouble
s.
A
fter checking thorough
ly
all path
once
again,
You should decide to replace BCM3550 o
r not.
A
ft
e
r ch
ec
kin
g th
e Po
w
e
r of RGB s
w
itch
y
ou
should decide
to replace component s
w
it
ch or
not.
A
ft
e
r ch
ec
kin
g th
e Po
w
e
r of MST
3361
y
ou
should decide
to replace MST3361 or not.
- 42 -
- HDMI doesn't display
Check input c
onnect P7007.
Can y
o
u see t
h
e n
o
rmal
w
a
v
e
form?
Check DDC commu
nication lines(IC7013
Pin5,6)
Check th
e in
pu
t o
f MST
3361
(IC7004)
This signal is
TMDS.
Can y
o
u see t
h
e n
o
rmal
w
a
v
e
form?
YE
S
YE
S
NO
P7007 may
hav
e
problem. Replace this Jack.
Check the output of
MST3361(IC7004 ).
Can y
o
u see t
h
e n
o
rmal
w
a
v
e
form?
YE
S
Check th
e in
pu
t an
d
outpu
t of
BCM3550(IC4006). Especially
y
ou should
ch
eck
The
H,V sy
nc and clock.
Can y
o
u see t
h
e n
o
rmal
w
a
v
e
form?
YE
S
NO
NO
A
ft
e
r ch
ec
kin
g th
e trace o
f
TMDS lin
es a
n
d po
w
e
r o
f
MST3361, y
ou should decide to replace MST3361 or
not.
NO
YE
X
This board ha
s big
problem
because Main
chip(BCM3
550)
hav
e some trouble
s.
A
fter checking thorough
ly
all path
once
again,
You should decide to replace BCM3550 o
r not.
A
ft
e
r checking the Po
w
e
r
of this chip, y
ou
should decide
to replace this or not.
A
ft
e
r ch
ec
kin
g th
e Po
w
e
r of MST
3361
y
ou
should decide
to replace MST3361 or not.
YE
S
Check HD
CP co
mmunicatio
n lin
es(IC7005
Pin5,6)
NO
A
ft
e
r checking the Po
w
e
r
of this chip, y
ou
should decide
to replace this or not.
- 43 -
300
200
310
500
510
120
820
801
802
803
800
804
600
610
530
520
400
810
840
900
807
830
805
806
EXPLODED VIEW
200T
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