LG 37LH4000 / 37LH4010 / 37LH4020 (CHASSIS:LD91G) Service Manual ▷ View online
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4.5. V-COM Adjust(Only 37/42/47LH4000-ZA)
- Why need Vcom adjustment?
A
The Vcom (Common Voltage) is a Reference Voltage of
Liquid Crystal Driving.
Liquid Crystal Driving.
-> Liquid Crystal need for Polarity Change with every frame.
- Adjust sequence
· After enter Service Mode by pushing “ADJ” key.
· Enter V-Com Adjust mode by pushing “
· Enter V-Com Adjust mode by pushing “
G
” key at “10. V-
Com”
· As pushing the right or the left button on the remote
controller, Find the V-COM value that is stopped the Flicker.
· If there is no flicker at default value, turn down or turn up at
least 20 step and check the flicker. Then go to the default
value.
value.
· Push the store button by “OK” key in the ADJ remocon.
4.6. Outgoing condition Configuration
- When pressing IN-STOP key by SVC remocon, Red LED are
blinked alternatively. And then Automatically turn off.
(Must not AC power OFF during blinking)
Confirm whether is normal or not when between power
board's ac block and GND is impacted on 1.5kV(dc) or
2.2kV(dc) for one second
board's ac block and GND is impacted on 1.5kV(dc) or
2.2kV(dc) for one second
5. Serial number D/L
• press “Power on” key of service remocon.
(Baud rate : 115200 bps)
• Connect RS232 Signal Cable to RS-232 Jack.
• Write Serial number by use RS-232.
• Must check the serial number at the Diagnostics of SET UP
• Write Serial number by use RS-232.
• Must check the serial number at the Diagnostics of SET UP
menu. (Refer to below).
5.1. Signal TABLE
CMD : A0h
LENGTH : 85~94h (1~16 bytes)
ADH : EEPROM Sub Address high (00~1F)
ADL : EEPROM Sub Address low (00~FF)
Data : Write data
CS : CMD + LENGTH + ADH + ADL + Data_1 +…+ Data_n
Delay : 20ms
LENGTH : 85~94h (1~16 bytes)
ADH : EEPROM Sub Address high (00~1F)
ADL : EEPROM Sub Address low (00~FF)
Data : Write data
CS : CMD + LENGTH + ADH + ADL + Data_1 +…+ Data_n
Delay : 20ms
5.2. Command Set
* Description
FOS Default write : <7mode data> write
Vtotal, V_Frequency, Sync_Polarity, Htotal, Hstart, Vstart, 0,
Phase
Data write : Model Name and Serial Number write in
Vtotal, V_Frequency, Sync_Polarity, Htotal, Hstart, Vstart, 0,
Phase
Data write : Model Name and Serial Number write in
EEPROM,.
5.3. method & notice
A. Serial number D/L is using of scan equipment.
B. Setting of scan equipment operated by Manufacturing
B. Setting of scan equipment operated by Manufacturing
Technology Group.
C. Serial number D/L must be conformed when it is produced
in production line, because serial number D/L is mandatory
by D-book 4.0.
by D-book 4.0.
CMD
LENGTH
ADH
ADL
DATA_1
. . .
Data_n
CS
DELAY
No. Adjust
mode
CMD(hex)
LENGTH(hex)
Description
1
EEPROM WRITE
A0h
84h+n
n-bytes Write (n = 1~16)
Row Li ne
Column Line
C
LC
C
ST
Pane l
S
Y
S
T
E
M
Gat
e
Driv
e
IC
So urce D r i v e I C
Circuit Block
Ti m i n g
Co nt r o ll e r
Co nt r o ll e r
Po w e r
Blo ck
Blo ck
V
COM
Ga mma
Re f e r e nce V o ltage
Re f e r e nce V o ltage
Gamm a R eference
Volta ge
Volta ge
Da ta (R ,G,B ) & C ont ro l s ignal
Con t rol si gnal
Data (R ,G,B ) &
Con t rol si gnal
Con t rol si gnal
In
te
te
r
fa
c
e
TFT
Po w e r I n p u t
Power Input
Da t a I n p u t
Da t a I n p u t
V
COM
Liquid
Crys tal
Crys tal
V
COM
(Visual Adjust and control the Voltage level)
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1. TV/CATV doesn’t display
TROUBLESHOOTING
2. DTV doesn’t display
Check the output data of TU1200 Pin 4,21,22.
Can you see the normal signal?
NO
Could you measure voltage of TU1200 &
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.
Check TU1200.
Can you see the normal signal?
Check the output of TR(Q1201).
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 TU1200 &
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 (Q1201) 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.
- 15 -
3. AV 1/2 doesn’t display
Check JK1100, JK1101
Can you see the normal waveform?
NO
JK1100, JK1101 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. Component doesn’t display
Check JK400
Can you see the normal waveform?
YES
NO
JK400
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.
- 16 -
5. RGB PC doesn’t display
Check P400 ,
Can you see the normal waveform?
NO
P400
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
6. HDMI doesn’t display
Check input connect JK600, JK601, JK602
Can you see the normal waveform?
Check DDC communication lines(IC100,
IC107)
YES
YES
NO
JK600, JK601, JK602
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.
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