LG 42SL90QD-DA (CHASSIS:LT91L) Service Manual ▷ View online
Digital Audio (Optic)
RS-232C (Ctrl./SVC)
MAX3232
RS232 IC
DTV IF +/-
Component 1
Y Pb Pr
Audio L/R
Phone (for RGB)
SPDIF
RX/TX
RX/TX
Tuner CVBS, SIF
TS_Serial In
TS_clk, Sync, Val, Err
TS_Parallel In[0-7]l
TS_clk, Sync, Val, Err
TS_Parallel In[0-7]l
Buffer
CE6355
Intel Demod.
CVBS
RGB/H/V
EEPROM
AV1
RGB
USB2.0
USB DP/DM
MIC2019
O.C. Protector
+5V
+5V
XC5000
Tuner
Rear
DDR2 (1Gbit)
Qimonda / Hynix
NAND Flash
(512Mbit)
Digital AMP
NTP3100L
I2S
DDR_Data[0:15], DQS, DM …
Addr.[ ], ctrl. data
Saturn6
Saturn6
LGE3369A
LGE3369A
Data [0 … 7]
Addr[0…1], CS …
Addr[0…1], CS …
SCL, SDA_3.3V
LCD Module
(HD/FHD)
LVDS
Serial Flash
(32Mbit)
SPI
EEPROM
(512K)
CM3212
Sensor
SCL, SDA_3.3V
DDR2 (256Mbit)
Qimonda / Hynix
DDR_Data[0:15], DQS, DM …
Addr.[ ], ctrl. data
Audio L/R
Audio L/R
Audio L/R
Divx
HDMI 1
HDMI 2
HDMI 3
5V_HDMI1, HPD1, DDC SCL/SDA, CLK, DATA
LNA
RF Jack (Digital)
RF Jack (Analog)
XC5000
Tuner
Buffer
CE6355
Demod
LGE7329A
FRC
Component 2
Y Pb Pr
Audio L/R
Data [0 … 15]
ADD [0…15]
ADD [0…15]
Data [0 … 15]
ADD [0…15]
ADD [0…15]
HDMI 4
5V_HDMI3, HPD3, DDC SCL/SDA, CLK, DATA
Side
Rear
DDR2 (256Mbit)
Qimonda / Hynix
DDR2 (512Mbit)
Qimonda / Hynix
DDR_Data[0:15], DQS, DM …
Addr.[ ], ctrl. data
RF S/W
TMDS351
HDMI S/W
DATA, Clock
Select
Side
TLV320AIC1106
PCM CODEC
B/T HP L/R OUT
LBMS-2C66B4
B/T Module
B/T DM/DP
PCM
PCMSYNC
MCLK
MCLK
CVBS
AV2
Audio L/R
Normal
audio
Y
N
Move to No
video/No audio
video/No audio
No video
Normal audio
Normal audio
Check Back Light
On with naked eye
On with naked eye
On
Y
N
Check Power
Board
12v,5v etc.
Board
12v,5v etc.
Normal
voltage
Y
N
Replace Main Board
Replace T-con
Board or module
Board or module
OR
Repair Power
Board or parts
Board or parts
Check Power Board 20V or 24v output
Normal
voltage
voltage
Y
Replace Inverter
or module
or module
N
Repair Power
Board or parts
Board or parts
End
Always check & record S/W Version and White
Balance value before replacing the Main Board
Balance value before replacing the Main Board
Replace Main Board
Re-enter White Balance value
※Precaution
Established
date
Electronics 6-3
Standard Repair Process
Revised date
2008. 3 .26
1/13
LCD TV
Error
symptom
A. Video error
No video/ Normal audio
☞A3
☞A1
☞A2
☞A27
☞A7 & A4
First of all, Check whether all of cables between board is inserted properly or not.
(Main B/D↔ Power B/D, LVDS Cable,Speaker Cable,IR B/D Cable,,,)
1
Normal
voltage?
Check various
voltages of Power
Board ( 5V,12V,20V
or 24V…)
voltages of Power
Board ( 5V,12V,20V
or 24V…)
No Video/
No audio
No audio
Check and
replace
MAIN B/D
replace
MAIN B/D
Y
Replace Power
Board and repair
parts
Board and repair
parts
N
End
Standard Repair Process
A. Video error
No video/ No audio
☞A5
Established
date
Electronics 6-3
Revised date
2008. 3 .26
2/13
LCD TV
Error
symptom
2
Click on the first or last page to see other 42SL90QD-DA (CHASSIS:LT91L) service manuals if exist.