55LH90 (CHASSIS:LA92C) - LG TV Service Manual (repair manual). Page 9

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- 9 -
ADJUSTMENT INSTRUCTION
1. Application Object
This specification sheet applied to LA92C Chassis applied
LCD TV all models manufactured in TV factory.
2. Notes
(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 equipment.
(2) Adjustments must be done in the correct order.
(3) The adjustments must be performed in the circumstance of
20±5°C of temperature and 65±10% of relative humidity if
there is no specific designation.
(4) The input voltage of the receiver be must kept 100V-240V,
50/60Hz when adjusting.
(5) The receiver must be operated for about 5 minutes prior to
the adjustment when module is in the circumstance of over
15.
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 480i Comp1 adj.(Comp1080i & RGB Adjust use
internal pattern) 
- 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-Star Menu 1.ADJUST
CHECK.
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)
4. Board-level adjustment 
4.1. ADC Adjustment
(1) Overview
ADC adjustment is needed to find the optimum black level
and gain in Analog-to-Digital device and to compensate
RGB deviation.
(2) Equipment & Condition
1) Jig (RS-232C protocol)
2) Input : MSPG-925FS(Model : 209 ,Pattern : 65, Only
component)) 
3) RGB Adjust use internal pattern.  
(3) Adjustment
1) Adjustment method
- Using RS-232, adjust items listed in 3.1 in the other
shown in “4.1.3.3”
2) Adj. protocol
Ref.) ADC Adj. RS232C Protocol_Ver1.0
3) Adj. order
- ad 00 00  [Enter ADC adj. mode]
- ad 00 10  [Adjust 480i Comp1] 
- ad 00 90  End adj.
Protocol
Command
Set ACK
Enter adj. mode
aa 00 00
a 00 OK00x
Begin adj.
ad 00 10
Return adj. result
OKx (Case of Success)
NGx (Case of Fail)
Read adj. data
(main)
(main)
ad 00 20 
000000000000000000000000007c007b006dx
(sub)
(Sub)
ad 00 21
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
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