42LH50 (CHASSIS:LA91L) - LG TV Service Manual (repair manual). Page 10

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This specification sheet applied to LA91L Chassis applied
LCD TV all models manufactured in TV factory.

(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.

• MAC Address Download, ESN Key Write 
• Adjust 720P Comp1 
• Adjust 1024*768 RGB 
• 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.

• White Balance adjustment 
• RS-232C functionality check 
• PING Test 
• Factory Option setting per destination 
• Ship-out mode setting (In-Stop) 

• Ship-out mode
• Service Option Default
• USB Download(S/W Update, Option, Service only)
• ISP Download(Option)

(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) MSPG-925 Series Pattern Generator(MSPG-925FA)

- Resolution : 720p Comp1 (MSPG-925FA: model-209,

pattern-65)

1024*768 RGB (MSPG-925FA: model-60 , pattern-65)

- Pattern : Horizontal 100% Color Bar Pattern
- Pattern level : 0.7±0.1 Vp-p
- Image

(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

- aa 00 00  [Enter ADC adj. mode]
- xb 00 40  [Change input source to Component1(480i)]
- ad 00 10  [Adjust 480i Comp1]
- xb 00 60  [Change input source to RGB(1024*768)]
- ad 00 10  [Adjust 1024*768 RGB]
- ad 00 90  End adj.

Protocol

Command

Set ACK 

Enter adj. mode 

aa 00 00 

a 00 OK00x 

Source change 

xb 00 40 

xb 00 60   

b 00 OK40x (Adjust 720p Comp1 ) 

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