White Balance Adjustment - LG 55LB65 Series Service Manual

4.2. White Balance Adjustment

4.2.1. Overview
▪ 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) Adjustment condition : normal temperature
1) Surrounding Temperature : 25 °C ± 5 °C
2) Surrounding Humidity : 20 % ~ 80 %
4.2.2. Equipment
(1) Color Analyzer: CA-210 (LED Module : CH 14)
(2) Adjustment Computer(During auto adj., RS-232C protocol
is needed)
(3) Adjustment Remote control
(4) Video Signal Generator MSPG-925F 720p/204-Gray
(Model: 217, Pattern: 49)
→ Only when internal pattern is not available
▪ Color Analyzer Matrix should be calibrated using CS-1000.
4.2.3. Equipment connection MAP
Probe
USB to RS-232C
* If TV internal pattern is used, not needed
4.2.4. Adj. Command (Protocol)
<Command Format>
START 6E A 50 A LEN A 03 A
- LEN: Number of Data Byte to be sent
- CMD: Command
- VAL: FOS Data value
- CS: Checksum of sent data
- A: Acknowledge
Ex) [Send: JA_00_DD] / [Ack: A_00_okDDX]
▪ RS-232C Command used during auto-adjustment.
RS-232C COMMAND
[CMD ID DATA]
wb 00 00
wb 00 10
wb 00 1f
wb 00 20
wb 00 2f
wb 00 ff
Ex) wb 00 00 -> Begin white balance auto-adj.
wb 00 10 -> Gain adj.
ja 00 ff -> Adj. data
jb 00 c0
...
...
wb 00 1f → Gain adj. completed
*(wb 00 20(Start), wb 00 2f(end)) → Off-set adj.
wb 00 ff → End white balance auto-adj.
Copyright © LG Electronics. Inc. All rights reserved.
Only for training and service purposes
Color Analyzer
RS-232C
Computer
RS-232C
* Pattern Generator
Signal Source
CMD A 00 A VAL A
Explanation
Begin White Balance adjustment
Gain adjustment(internal white pattern)
Gain adjustment completed
Offset adjustment(internal white pattern)
Offset adjustment completed
End White Balance adjustment
(internal pattern disappears )
▪ Adj. Map
Applied Model : LD42B Chassis ALL MODELS
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
4.2.5. Adj. method
(1) Auto adj. method
1) Set TV in adj. mode using P-Only key.
2) Zero calibrate probe then place it on the center of the
Display.
3) Connect Cable.(RS-232C to USB)
4) Select mode in adj. Program and begin adj.
5) When adj. is complete (OK Sign), check adj. status pre
mode. (Cool, Medium, Warm)
6) Remove probe and RS-232C cable to complete adj.
▪ W/B Adj. must begin as start command "wb 00 00" , and
finish as end command "wb 00 ff", and Adj. offset if need.
CS STOP
(2) Manual adjustment. method
1) Set TV in Adj. mode using P-Only key.
2) Zero Calibrate the probe of Color Analyzer, then place it
on the center of LCD module within 10 cm of the surface.
3) Press ADJ key → EZ adjust using adj. R/C → 7. White-
Balance then press the cursor to the right(key ►).
(When right key(►) is pressed 204 Gray internal pattern
will be displayed)
4) One of R Gain / G Gain / B Gain should be fixed at 192,
and the rest will be lowered to meet the desired value.
5) Adjustment is performed in COOL, MEDIUM, WARM 3
modes of color temperature.
▪ If internal pattern is not available, use RF input. In EZ Adj.
menu 7.White Balance, you can select one of 2 Test-
pattern: ON, OFF. Default is inner(ON). By selecting OFF,
you can adjust using RF signal in 204 Gray pattern.
▪ Adjustment 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°)
- 16 -
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)