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LG 22LN41 Series Service Manual page 10

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4. White Balance Adjustment
4.1. Overview
4.1.1. W/B adj. Objective & How-it-works
(1) Objective: To reduce each Panel's W/B deviation
(2) How-it-works: When R/G/B gain in the OSD is at 192, it
means the panel is at its Full Dynamic Range. In order to
prevent saturation of Full Dynamic range and data, one of
R/G/B is fixed at 192, and the other two is lowered to find
the desired value.
(3) Adj. condition: normal temperature
1) Surrounding Temperature: 25 °C ± 5 °C
2) Warm-up time: About 5 Min◦
3) Surrounding Humidity: 20% ~ 80%
4) Before White balance adjustment, Keep power on
status, don't power off
4.1.2. Adj. condition and cautionary items
(1) Lighting condition in surrounding area surrounding lighting
should be lower 10 lux.
Try to isolate adj. area into dark surrounding.
(2) Probe location: Color Analyzer(CA-210) probe should be
within 10 cm and perpendicular of the module surface
(80°~ 100°)
(3) Aging time
1) After Aging Start, Keep the Power ON status during 5
Minutes.
2) In case of LCD, Back-light on should be checked using
no signal or Full-white pattern.
4.2. Equipment
(1) Color Analyzer: CA-210 (NCG: CH 9 / WCG: CH12 / LED:
CH14)
(2) Adj. Computer (During auto adj., RS-232C protocol is
needed)
(3) Adjust Remocon
(4) Video Signal Generator MSPG-925F 720p/204-Gray
(Model: 217, Pattern: 49)
* Color Analyzer Matrix should be calibrated using CS-1000.
4.3. Equipment connection
Probe
* If TV internal pattern is used, not needed
4.4. Adjustment Command (Protocol)
(1) RS-232C Command used during auto-adj.
RS-232C COMMAND
CMD
DATA
ID
wb
00
00
Begin White Balance adjustment
End White Balance adjustment
wb
00
ff
(internal pattern disappears )
Copyright ©
LG Electronics. Inc. All rights reserved.
Only for training and service purposes
Co lo r Analyzer
RS -232C
Co m p ut er
RS -232C
RS -232C
Pat t ern Generat o r
Signal Source
Explantion
(2) Adjustment Map
Adj. item
R Gain
G Gain
B Gain
Cool
R Cut
G Cut
B Cut
R Gain
G Gain
B Gain
Medium
R Cut
G Cut
B Cut
R Gain
G Gain
B Gain
Warm
R Cut
G Cut
4.5. Adjustment method
4.5.1. Auto WB calibration
(1) Set TV in ADJ mode using P-Only key(or POWER ON key).
(2) Place optical probe on the center of the display.
- It need to check probe condition of zero calibration before
adjustment.
(3) Connect RS-232C Cable
(4) Select mode in ADJ Program and begin a adjustment.
(5) When WB adjustment is completed with OK message,
check adjustment status of pre-set mode. (Cool, Medium,
Warm)
(6) Remove probe and RS-232C cable.
▪ W/B Adj. must begin as start command "wb 00 00" , and
finish as end command "wb 00 ff", and Adj. offset if need.
4.5.2. LED White balance table
- If Model is Polaris Model, G-gain fix is applied.
(1) Cool Mode
1) Purpose : Adjust the color temperature to reduce the
deviation of the module color temperature.
2) Principle : To adjust the white balance without the
saturation, Fix the G gain to 172 (default data) and
change the others (R/B Gain ).
3) Adjustment mode : mode - Cool
(2) Medium / Warm Mode
1) Purpose : Adjust the color temperature to reduce the
deviation of the module color temperature.
2) Principle : To adjust the white balance without the
saturation, Fix the one of R/G/B gain to 192 (default
data) and decrease the others.
3) Adjustment mode : Two modes - Medium / Warm
- 10 -
Command
Data Range
(lower caseASCII)
(Hex.)
CMD1
CMD2
MIN
MAX
j
g
00
C0
j
h
00
C0
j
i
00
C0
j
a
00
C0
j
b
00
C0
j
c
00
C0
j
d
00
C0
j
e
00
C0
j
f
00
C0
LGE Internal Use Only
Default
(Decimal)

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