LG 21FG5RG, Service Manual

Page: 6 / 22

1. Scope of Application
These instructions are applied to CW81B Chassis.
2. Notes
1) Because this is a cold chassis, it is not necessary to use an
isolation transformer. However, operating it using a
transformer between the power supply line and chassis input
to prevent electric shock and to protect the test instrument.
2) All adjustment must be done in the correct sequence.
However, for better productivity, it can be change in a pre-
permitted range.
3) Environment conditions : If not specified, it must be done in
following conditions.
Temperature : 25 ± 5°C
Humidity: 60% ± 10%
4) Power supply of SET for PAL/SECAM
China/indonesia/Vietnam/CIS Market: AC100~240V±10%,
50/60Hz.
5) If not specified, the receiver must be operated for more than
20 minutes prior to the adjustment.
6) Signal : Received the standard color signal (65dB±1dBuV).
PAL/SECAM: LG standard signal means the digital pattern
PAL-B/G 05CH.
7) If not specified, APC ON is APC CLEAR (DYNAMIC)
3. AGC Voltage Adjustment
3-1. Necessary Instrument
- Digital Multi-meter: 1 set
- Max Input Current : Over 1A/ Max Input Voltage : 500Vdc
- Measurement Range : 10mV-100mVdc/ Accuracy : 0.03%
3-2. Adjustment Preparation
1) Input in the 75
Ω
cable 65dB(±1dB) LG standard signal.
2) Connect the multi-meter to J105 (AGC Check, Marking).
3-3. Adjustment
1) Press the “INSTART” key of factory remote control and
select “VP0 (RF AGC)” adjustment mode.
2) Press the VOL+/- (
F
/
G
) key until the multi-meter shows
reading as shown below.
3) CAUTION: Since the signal strength can be easily
changed by the condition of signal cable, you need to
check the signal strength frequently in order to prevent
error.
4. Screen Voltage Adjustment
4-1. Adjustment
(Using Factory Remote Control)
1) Input in the 75
Ω
cable LG standard signal (Digital Pattern,
480NC).
2) Press the “ADJ’ key of factory remote control once to make
the TV set display horizontal line.
3) Turn the screen volume on the FBT clockwise until the
horizontal line is visible and turn it counterclockwise until
horizontal line faintly visible.
(Exit screen voltage adjustment by press “Enter(
A
)” key of
factory remote control.)
5. Purity and Convergence Adjustment
5-1. Purity adjustment
(1) Adjustment Preparation
1) Receive Red Raster Pattern for purity adjustment (51CH).
2) Demagnetize the CPT and Cabinet with a degaussing coil.
(2) Adjustment
1) Pre-adjust the static convergence (STC) with the 4 and
6pole magnet.
2) If the horizontal Line is inline with CPT Mark, 2-Pole
magnet should direct 3-9 o’clock direction.
3) If not, direct 2-pole magnet handle toward 6-12 o’clock
direction and adjust the Horizontal Line to fall onto the
mark opening the magnet at an angle.
4) Push the DY(deflection yoke) all the way to the CPT
funnel.
5) Turn the purity magnet(2-pole magnet) so that the “green”
color portion of left side and the “blue” color portion on the
right side have equal amount of color.
6) Pull the DY slowly backward and fix it when the whole
screen becomes red.
(The specified torque for fixing DY screw should be
10Kg/cm.)
5-2. Convergency Adjustment
(1) Necessary Instrument
1) Degaussing Coil
2) Convergency fixing instrument (Speical tools)
(2) Adjustment Preparation
1) Operate the unit at least 15 minutes before adjustment.
2) Using degaussing coil, remove the stains on CPT &
Cabinet.
3) Received the Cross Hatch Pattern of Convergence. (09ch)
4) Let the Contrast in normal luminance level
.
(3) Static Convergence (STC) Adjustment
1) Receive the Cross Hatch Pattern Convergence (09ch).
G R B
- 6 -
ADJUSTMENT
G R B
R G R B
6700NFNS11E
6700VS0002F
6700PF0006B
6870NB0026A
6700MF0014A
6700MF0014B
6700MF0018B
6700MF0018A
LGIT
LGIT
SANYO
LGIT
LGIT
LGIT
LGIT
LGIT
2.15 ± 0.05V
3.0 ± 0.05V
2.3 ± 0.05V
2.15 ± 0.05V
2.3 ± 0.05V
2.15 ± 0.05V
2.4 ± 0.05V
2.5 ± 0.05V
65dBu
70dBu
65dBu
65dBu
65dBu
65dBu
65dBu
65dBu
TAEA-H111F
TAEW-G002D
115-B-A86EL
TAEA-J001F
TAEW-G013D
TAEW-G017D
TAEA-G001D
TAEA-G011D
Korea
PAL
PAL
HITACHI
PAL
SECAM(CIS)
PAL
SECAM(CIS)
Tuner P/N Maker AGC Vol Signal Tuner Spec. Remark
Copyright©2008 LG Electronics.Inc. All right reserved.
Only for training and service purposes. LGE Internal Use Only