42LP645H (CHASSIS:LA3AA) - LG TV Service Manual (repair manual). Page 8

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ADJUSTMENT INSTRUCTION
1. Application
This  spec.  sheet  applies  to  LA3AZ/Y/X  Chassis  applied  LED 
TV all models manufactured in TV factory
2. Specification
(1)  Because this is not a hot chassis, it is not necessary to use 
an  isolation  transformer.  However,  the  use  of  isolation 
transformer will help protect test instrument.
(2) Adjustment must be done in the correct order.
(3)  The adjustment must be performed in the circumstance of 
25 ±5 ºC of temperature and 65±10% of relative humidity if 
there is no specific designation
(4)  The  input  voltage  of  the  receiver  must  keep  100~240V, 
50/60Hz
(5)  At first Worker must turn on the SET by using Power Only 
key.
(6)  The receiver must be operated for about 5 minutes prior to 
the adjustment when module is in the circumstance of over 
15 ºC
     In case of keeping module is in the circumstance of 0°C, it 
should be placed in the circumstance of above 15°C for 2 
hours
     In case of keeping module is in the circumstance of below 
-20°C,  it  should  be  placed  in  the  circumstance  of  above 
15°C for 3 hours.
 Caution
When  still  image  is  displayed  for  a  period  of  20  minutes  or 
longer (especially where W/B scale is strong.
Digital  pattern  13ch  and/or  Cross  hatch  pattern  09ch),  there 
can some afterimage in the black level area
 
3. Adjustment items
3.1. Board Level Adjustment
▪Adjust RGB (ADC)
▪EDID/DDC download
■  Above  adjustment  items  can  be  also  performed  in  Final 
Assembly  if  needed.  Both  Board-level  and  Final  assembly 
adjustment  items  can  be  check  using  In-Start  Menu  1.
ADJUST CHECK.
   RGB-PC Adjust will be calculated by 480i adjust value.
3.2. Final assembly adjustment
▪White Balance adjustment
▪RS-232C functionality check
▪Factory Option setting per destination
▪Ship-out mode setting (In-Stop)
3.3. Etc
▪Ship-out mode
▪Service Option Default
▪USB Download(S/W Update, Option, Service only)
▪ISP Download (Optional)
4. Automatic Adjustment
4.1. ADC Adjustment
4.1.1. Overview
▪  ADC  adjustment  is  needed  to  find  the  optimum  black  level 
and gain in Analog-to-Digital device and to compensate RGB 
deviation.
4.1.2. Equipment & Condition
(1) Protocol: RS-232C
(2) Inner Pattern
- Resolution : 1024*768(RGB)
- Pattern : Horizontal 100% Color Bar Pattern
- Pattern level : 0.7±0.1 Vp-p
4.1.3. Adjustment
4.1.3.1. Adjustment method
▪  Using RS-232, adjust items listed in 3.1 in the other shown in 
“4.1.3.3”
Protocol
Command
Set ACK
Enter adj. mode aa 00 00
a 00 OK00x
Source change
xb 00 60 
b 00 OK60x (Adjust 1024*768 RGB)
Begin adj.
ad 00 10
Return adj. 
result
OKx (Case of Success)
NGx (Case of Fail)
Read adj. data
(main)
ad 00 20 
(sub )
ad 00 21
(main)
000000000000000000000000007c007b006dx
(Sub)
000000070000000000000000007c00830077x
Confirm adj.
ad 00 99
NG 03 00x (Fail)
NG 03 01x (Fail)
NG 03 02x (Fail)
OK 03 03x (Success)
End adj.
aa 00 90
a 00 OK90x
Ref.) ADC Adj. RS232C Protocol_Ver1.0
4.1.3.3. ADC RGB
▪aa 00 00  [Enter ADC adj. mode]
▪xb 00 60  [Change input source to RGB(1024*768)]
▪ad 00 10  [Adjust 1024*768 RGB]
▪ad 00 90  End adj.
Ref) ADC adj. RS232C Protocol_Ver1.0
 
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