LG Lafinion 55 Service Manual Download

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1. Application Object

These instructions are applied to SC-023A chassis.

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 instrument.

(2) Adjustment must be done in the correct order.
(3) The adjustment must be performed in the circumstance of

25±5°C of temperature and 65±10% of relative humidity if
there is no specific designation.

(4) The input voltage of the receiver must keep

(100~240V)±10%, 50/60Hz in adjusting.

(5) The receiver must be operated for about 15 minutes prior

to the adjustment. But adjusting on the board can be done
in jig state right away.

(6) Signal : The standard color signal is approved in

65±1dBµV.
The standard color signal means digital pattern signal.

(7) If not specified, APC ON is CLEAR.

3. AGC Voltage Adjustment

3.1 Preliminary steps

(1) Input 65dB(±1dB) digital pattern signal into 75

Ω

antenna

terminal.

(2) Connect digital multimeter to the C102 left terminal(with

Hole/J5) marking with AGC Check.

3.2 Adjustment

(1) Select the SUB 0(RF AGC) mode with a INSTART Key.
(2) Adjust the adjustment data with VOL +, - key until the

digital multimeter voltage show 2.2±0.05V.

(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
misadjustment.

4. Screen Voltage Adjustment

4.1 Preliminary steps

(1) Input digital pattern signal into 75

Ω

terminal.

(2) Set Picture condition to “CLEAR”.

CLEAR

CONTRAST : 100
BRIGHTNESS : 50
COLOR : 50
SHARPNESS : 50
TINT : 0

4.2 Adjustment

(1) Press “ADJ” or “SVC” button on the remote control to make

one horizontal line.

(2) Turn the Screen volume not to see one horizontal line and

turn oppositely until it starts to display.

5. Purity and Convergence Adjustment

5.1 Purity Adjustment

(1) Preliminary steps

1. Receive Red Raster Pattern.
2. Degauss CPT and Cabinet with degaussing coil.

(2) Horizontal Line Adjustment

1. Pre-adjust Static Convergence(STC) with 4-pole & 6-

pole magnet.

2. Check if the beam lands at mask hole by setting two 2-

Pole magnets in opposite direction repectively.

3. If not, adjust 2-Pole magnet so the beam as to land at

mask hole accurately.

(3) Purity Adjustment

1. Adhere DY closely to CPT.
2. Receive Red Pattern and adjust the 2-Pole magnet so

Red Color Bar as to locate center and make the portion
of Green color and Blue color same. <Fig. 1>
(Be careful of HALO if two 2-Pole magnet are open over
30 degree)

3. Make the full screen Red by pulling DY back slowly.

<Fig. 2>
(When adhering DY, use the electric driver of which
turning force is lower than 10Kg/Cm.)

5.2 Convergence Adjustment

(1) Test equipment

1. Degaussing Coil
2. Convergence fixing jig

(2) Preliminary steps

1. Heat run over 30 minutes before adjustment.
2. Degauss CPT and Cabinet with degaussing coil.
3. Rececive Cross Hatch Pattern.
4. Adjust Contrast and Brightness for easy observation.

(3) Static Convergence (STC) Adjustment

1. Receive Crosshatch Pattern.
2. Adjust Focus with focus volume.
3. Open two 4-Pole magnets until vertical Red and Blue

lines are unified.

4. Rotate the 4-Pole magnets keeping the angle between

two 4-Pole magnets until horizontal Red and Blue lines
are unified.

5. Open two 6-Pole magnets until vertical Red and Green

lines are unified.

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ADJUSTMENT INSTRUCTION