LG 55LH45YD (CHASSIS:LC91B) Service Manual ▷ View online
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1. TV/CATV doesn’t display
TROUBLESHOOTING
2. DTV doesn’t display
Check the output data of TU1100 Pin 20,21,22
Can you see the normal signal?
NO
Could you measure voltage of TU1100 &
IIC lines?
Are they all normal?
NO
You should check power line
& IIC lines.
YES
You should replace Main Board.
YES
Check the output of Main IC(IC100).
Especially you should check
The H,V sync and clock.
Can you see the normal waveform?
YES
NO
After checking the Power of Main IC(IC100) you
should decide to replace Main IC or not.
This board has big problem because Main
IC(IC100) have some troubles.
After checking thoroughly all path once again,
You should decide to replace Main Board or not.
Could you measure voltage of IC1200 & IIC
lines?
Are they all normal?
NO
You should check power line
& IIC lines.
YES
Check TU1100.
Can you see the normal signal?
Check the output of TR(Q1102).
Can you see the normal waveform?
Check the output of Main IC(IC100).
Especially you should check
The H,V sync and clock.
Can you see the normal waveform?
YES
YES
NO
Could you measure voltage of TU1100 &
IIC lines?
Are they all normal?
YES
NO
You should check power line
& IIC lines.
YES
You should replace Main Board.
NO
You should decide to replace TR (Q1102) or not.
NO
After checking the Power of Main IC(IC100) you
should decide to replace Main IC or not.
This board has big problem because Main
IC(IC100) have some troubles.
After checking thoroughly all path once again,
You should decide to replace Main Board or not.
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3. Component1/2, AV1/2, S-Video doesn’t display
Check JK500, JK501, JK402
Can you see the normal waveform?
NO
JK500, JK501,JK402 may have problem.
Replace this Jack.
Check the output of Main IC(IC100).
Especially you should check
The H,V sync and clock.
Can you see the normal waveform?
YES
NO
After checking the Power of Main IC(IC100) you
should decide to replace Main IC or not.
This board has big problem because Main
IC(IC100) have some troubles.
After checking thoroughly all path once again,
You should decide to replace Main Board or not.
YES
4. RGB PC doesn’t display
Check JK404 ,
Can you see the normal waveform?
NO
JK404 may have problem.
Replace this Jack.
Check the output of Main IC(IC100).
Especially you should check
The H,V sync and clock.
Can you see the normal waveform?
YES
NO
After checking the Power of Main IC(IC100) you
should decide to replace Main IC or not.
This board has big problem because Main
IC(IC100) have some troubles.
After checking thoroughly all path once again,
You should decide to replace Main Board or not.
YES
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5. HDMI doesn’t display
Check input connect JK600, JK601,
JK602,JK603
Can you see the normal waveform?
Check DDC communication
lines(IC600,IC601,IC602,IC604)
YES
YES
NO
JK600, JK601, JK602,JK603
may have problem. Replace this Jack.
NO
After checking the Power of this chip, you
should decide to replace this or not.
YES
Check HDCP communication lines(IC107)
NO
After checking the Power of this chip, you
should decide to replace this or not.
Check the output of Main IC(IC100).
Especially you should check
The H,V sync and clock.
Can you see the normal waveform?
YES
NO
After checking the Power of Main IC(IC100) you
should decide to replace Main IC or not.
This board has big problem because Main
IC(IC100) have some troubles.
After checking thoroughly all path once again,
You should decide to replace Main Board or not.
Check the input/output data of HDMI
Switch (IC603) & DDC line
NO
After checking the Power of this chip, you
should decide to replace this or not.
YES
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BLOCK DIAGRAM
Saturn6
LGE3369A
(IC100)
Saturn6
Saturn6
LGE3369A
LGE3369A
(IC100)
(IC100)
Serial FLASH for boot
(32M, IC103)
Serial FLASH for boot
Serial FLASH for boot
(32M, IC103)
(32M, IC103)
5 : SPI, Flash_WP_1
EEPROM
(512K, IC105)
EEPROM
EEPROM
(512K, IC105)
(512K, IC105)
2 :
EEPROM_SCL, SDA
HDCP EEPROM
(8K, IC107)
HDCP EEPROM
HDCP EEPROM
(8K, IC107)
(8K, IC107)
2 :
EEPROM_SCL, SDA
NAND FLASH
(512M, IC102)
NAND FLASH
NAND FLASH
(512M, IC102)
(512M, IC102)
14 : PCM_A[0:7],
°¶
DDR2
(512M, IC301)
DDR2
DDR2
(512M, IC301)
(512M, IC301)
45 : DDR2_D[0:15],
°¶
DDR2
(1G, IC300)
DDR2
DDR2
(1G, IC300)
(1G, IC300)
45 : DDR2_D[0:15],
°¶
Audio AMP
(NTP3100, IC701)
Audio AMP
Audio AMP
(NTP3100, IC701)
(NTP3100, IC701)
6 : I2S, MCLK,
°¶
2 : SCL, SDA_SUB/AMP
Demodulator
(LGDT3900, IC1200)
Demodulator
Demodulator
(LGDT3900, IC1200)
(LGDT3900, IC1200)
SDRAM
(64M, IC1201)
SDRAM
SDRAM
(64M, IC1201)
(64M, IC1201)
4 : TS_SERIAL,
°¶
2 : FE_DEMOD_
SCL/SDA
2 : TU_IF_OUT+/-
1 : FE_MAIN(CVBS)
1 : FE_SIF
Comp 1
Comp 2
AV 1
AV 2(SIDE)
RGB
Comp 1
Comp 2
AV 1
AV 2(SIDE)
HDMI 1
HDMI 3
(SIDE)
Digital Audio (Optic)
Phone (for RGB)
USB 2.0(SIDE)
RS-232C :
Ctrl& SVC
EEPROM
(2K, IC600)
EEPROM
EEPROM
(2K, IC600)
(2K, IC600)
EEPROM
(2K, IC601)
EEPROM
EEPROM
(2K, IC601)
(2K, IC601)
EEPROM
(2K, IC400)
1 : EDID_WP
12 : DATA+/-X3, CLK+/-, V_HDMI1, DDC_SCL1/SDA1
2 : DDC_SCL1/SDA1
12 : DATA+/-X3, CLK+/-, HPD3, 5V_HDMI3 DDC_SCL3/SDA3
2 : DDC_SCL3/SDA3
TUNER
(TDFR-Z751D,
TU1100)
TUNER
TUNER
(TDFR-Z751D,
(TDFR-Z751D,
TU1100)
TU1100)
2 : CVBS, DET
5 : S_Y, S_C, S_DET, CVBS, DET
4
: Y
,
P
b
, Pr,
DET
4
: Y
,
P
b
, Pr,
DET
1 : EDID_WP
8 : R, G, B, H/VSYNC, DET, ISP_RXD/TXD
2 : ISP_RXD/TXD
2 : L/R
2 : L/R
2 : L/R
2 : L/R
2 : L/R
1 : SPDIF_OUT
OCP
(MP6211,IC402)
MAX3232CDR
(IC403)
MAX3232CDR
MAX3232CDR
(IC403)
(IC403)
2 : DBG_
RX/TX
2 : SIDE_USB_DM/DP
2 : DBG_
RX/TX
1 : 5V_USB
2 : USB_CTL,
USB_OCD
Sub
(IR/LED, Control)
Sub
Sub
(IR/LED, Control)
(IR/LED, Control)
1 : LED_ON
2 : SCL, SDA_SUB/AMP
3 : IR, KEY1/2
HDMI 2
Switch
(TMDS351, IC603)
Switch
Switch
(TMDS351, IC603)
(TMDS351, IC603)
EEPROM
(2K, IC602)
EEPROM
EEPROM
(2K, IC602)
(2K, IC602)
FRC
(LGE7329A, IC900)
FRC
FRC
(LGE7329A, IC900)
(LGE7329A, IC900)
DDR2
DDR2
(512M, IC1000)
(512M, IC1000)
DDR2
DDR2
(512M, IC1001)
(512M, IC1001)
45 : DDR2_D[0:15],
°¶
45 : DDR2_D[0:15],
24: LVDS data 50/60Hz
LCD module (Scanning BLU)
LCD module (Scanning BLU)
LCD module (Scanning BLU)
PWM_DIM,
LVDS/BIT_SEL,
OPC_EN
OPC_OUT1/2
LIPS(42/47),PSU(55)
LVDS data 100/120Hz
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