LG 42LH40 (CHASSIS:LA92G) Service Manual ▷ View online
- 21 -
8. All Source Audio
Check Mstar I2S Output
R604, R605, R606
Check IC600 Power
*20V, 3.3V, 1.8V.
OK
OK
Make sure you can’t hear any audio.
OK
First check the TV SPEAKER Menu
Toggle the menu.
OK
Check Mstar AUDIO_MASTER_CLK
OK
Check Connector & P600
Check Regulator IC601, IC704.
No
Check signal line. Or replace IC100.
No
Replace Mstar(IC100) or Main board.
No
No
Check Output Signal P600 1, 2, 3, 4 pin.
OK
Replace NTP(Audio AMP).
No
Replace connector if found to be damaged.
No
OK
Check speaker resistance
and connector damage.
Replace speaker.
No
- 22 -
10. Analog TV Audio
Check RF Cable.
OK
Check SIF buffer signal.
Check SIF Signal line.
No
OK
Check Tuner 5V Power
TU1001 4pin
Check IC1002.
No
Bad Tuner
Replace Tuner.
No
OK
Follow procedure All source audio
trouble shooting guide.
Replace Mstar(IC100)
or Main board.
No
9. Digital TV Audio
Check Tuner 5V Power
TU1001 4pin.
Check IC1002.
No
OK
Check IF_P/N Signal.
Bad Tuner. Replace Tuner
No
OK
Check Demodulator Input
Clock(X1005-25MHz).
Replace X1005.
No
OK
Check IC400(LGDT) Output
-AR1070, AR1071
Replace IC1004.
No
OK
Check Output Signal
P600 1, 2, 3, 4 pin
Replace NTP(Audio AMP)
IC600
No
OK
Check speaker resistance
and connector damage.
Replace speaker.
No
OK
Check Connector & P600
Replace connector
if found to be damaged.
No
- 23 -
11. No Video
Check 3.3V/16V/26V DC Voltage
- R1447, R1446, R1450
Replace IC300 or Main board.
No
OK
Check 12V DC Voltage
- L1300
Check Q706
- pin4 2V DC voltage
No
Check PANEL_CTRL
- LOW(0V)
No
OK
Replace Q706
OK
Replace LCD Module.
OK
Check IC1301 pin 28(Vcom)
- about 7V
OK
Check URSA2 mini-LVDS output
P1400, P1401
Detach the P1400/P1401
FFC Cable
No
Replace LCD Module.
No
Replace IC1301.
No
- 24 -
BLOCK DIAGRAM
D-sub RGB
HDMI 1
Side A
V
CV
BS
, L
/R
DDR2 (5
12Mbit)
Qimonda
/ Hynix
NAND Flash
(256Mb)
Digita
l A
udio
(Optic
)
Digita
l AMP
NT
P3000A
RS-232C (Ctrl./SVC)
I2S
EEPROM
512Kb
RGB/
H/V
Half-NIM Tuner
DD
R_Data[
0:
15]
, D
Q
S,
DM …
Ad
dr.[ ]
, ctrl. data
MAX3
232
Saturn5
Saturn5
(ATSC
(ATSC
US)
US)
MPEG2
L
inux
Scal
er
He
adphone
D
a
ta [0 …
7
]
IF
+/-
SIF
TU_CVBS
R
e
set / IF
_AGC
…
SDA
/SCL_
5V
JT
A
G
C
L
K,T
D
I,T
D
O
,M
S,
R
S
T
HDMI3
Ad
dr[0…1], C
S
…
Au
d
io L/R
A
u
dio L/R (for
RGB)
HDMI 2
SP
DI
F
RX
/T
X
RX
/T
X
J
A
CK
P
A
CK
J
A
CK
P
A
CK
at RE
A
R
at RE
A
R
J
A
CK
P
A
CK
J
A
CK
P
A
CK
at SIDE
at SIDE
SCL
, SDA
_3
.3
V
T
R
B
u
ffer
VSB
Demod.
X-t
al
Res
et
S
w
itch
Reset IC
12MH
z
T
S
In[0…
7
]
TS_
cl
k, SOP, Va
l
EEPR
OM
Data[1
6
:31]
DDR2 (5
12Mbit)
AV
Component 1
Y
Pb
Pr, L/R
CV
BS
, Y/
C,
L
/R
Component 2
Y
Pb
Pr, L/R
Digital A
udio
(Coaxial)
USB2.0
SCL
, SDA
_3
.3
V
B
lu
e
tooth
Do
ngl
e
(Option)
DP
/D
M
DP
/D
M
O.C. Protector
+5V
+5V
LCD Mod
u
le
(FHD, 120
Hz)
FRC IC
(MST
7327)
DDR2
Qimonda/Hy
nix
FRC Block
FRC Block
T
T
-
-
c
on b
loc
k
c
on b
loc
k
LV
D
S
LCD Module
(FHD, 60
Hz)
Option
HDMI 3
HDMI S/W
Mini-LVDS
P-Gamm
a
V-Com
IIC
Qimonda
/ Hynix
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