LG 42LD465 Service Manual page 14

4.6. V-COM Adjust(Only LGD(M+S) Module)
- Why need Vcom adjustment?
A The Vcom (Common Voltage) is a Reference Voltage of
Liquid Crystal Driving.
-> Liquid Crystal need for Polarity Change with every frame.
Data (R ,G,B ) &
Con t rol si gnal
Ti m i n g
S
Co nt r o ll e r
Da t a I n p u t Da t a I n p u t
Y
S
T
E
Po w e r
Po w e r I n p u t Power Input
Blo ck
M
V
COM
V
COM
- Adjust sequence
· Press the PIP key of th ADJ remote control.(This PIP key is
hot key to enter the VCOM adjusting mode)
(Or After enter Service Mode by pushing "ADJ" key, then
Enter V-Com Adjust mode by pushing "
Com"
· As pushing the right or the left key on the remote control,
and find the V-COM value which is no or minimized the
Flicker. (If there is no flicker at default value, Press the exit
key and finish the VCOM adjustment.)
· Push the "OK" key to store value. Then the message
"Saving OK" is pop.
· Press the exit key to finish VCOM adjustment.
(Visual Adjust and control the Voltage level)
· V-COM default value is different from module.
1) 32LD450 : 417
2) 37LD450 : 432
3) 42LD450 : 433
Copyright LG Electronics. Inc. All right reserved.
Only for training and service purposes
Circuit Block
Ga mma
Re f e r e nce V o ltage
Data (R ,G,B ) & C ont ro l s ignal
Gamm a Reference
Volta ge
Con t rol si gnal
So urce D r i v e I C
Column Line
Pane l
V
COM
C
C
LC ST
Liquid
Crys tal
TFT
Row Li ne
G
" key at "10. V-
4.7. 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)
4.8. Internal pressure
Confirm whether is normal or not when between power
board's ac block and GND is impacted on 1.5 kV(dc) or 2.2
kV(dc) for one second.
- 14 - LGE Internal Use Only