LG CF25A50T ADJUSTMENT INSTRUCTIONS

ADJUSTMENT INSTRUCTIONS

*Safety Precautions

1. It is safe to adjust after using insulating transformer between the power supply line and chassis input to prevent the risk of electric shock and protect the instrument.

2. Never disconnect leads while the TV receiver is on.

3. Don't short any portion of circuits while power is on.

4. The adjustment must be done by the correct appliances. But this is changeable in view of productivity.

5. Unless otherwise noted, set the line voltage to 230Vac

+_10%, 50Hz.

* Test Equipment required

1. RF signal generator (with pattern generator)

2. DC Power Supply

3. Multimeter (volt meter)

4. Oscilloscope

5. Color analyzer

Main Board(Component side view)

MAIN BOARD

38.9MHz 10mVp-p

RF SIGNAL GENERATOR

5 0.1Vdc DC POWER SUPPLY

VL102

4.5M

CERAMIC CAP. 10000pF

TUNER

TP5

J156

AGC

VL101

PIF

TDA9811

17 16

TP1

IC101

TP3

30 32

Z102

CERAMIC CAP. 10000pF

VR101

VR102

ADJ.

AGC ADJ.

(TP point is on the copper side of PCB)

TP1 : pin23 of IC101 TP2 : pin9 of IC101 TP3 : pin30 of IC101 TP5 : J156

TP2

MULTIMETER

Frequency

38.9MHz

Modulation

OFF

Output level

10mVp-p

(Table 1)

* SECAM L' Adjustment

NOTE :This adjustment should be performed after PIF

adjustment.

Test Point : TP1

Adjust : VR101

1) Tune the TV set to receive a SECAM-L' signal.

2) Adjust VR101 so that the DC voltage may be indicated

+_0.1Vdc.

2.6

* SECAM L/L' sound Adjustment

Test Point : C638(Refer to the Fig.2)

Adjust : VL102

GND

MSP3410

AM INPUT

IC601

OSCILLOSCOPE

C638

J116

Fig. 2

Noise Level

Fig. 1 : Connection Diagram of Equipment for PIF Adjustment

* PIF (Picture Intermediate Frequency) Adjustment

Test Point : TP1

Adjust : VL101

1) Connect the measuring equipment to the Main Board as shown in Fig.1.

2) Set RF frequency and output level of RF SIGNAL GENERATOR as shown Table 1.

3) Turn on DC power supply.

4) Adjust VL101 so that the DC voltage may be indicated

+_0.1Vdc.

2.6

(Before Adjustment) (After Adjustment)

1) Connect the Oscilloscope to the Main Board as shown in Fig. 2.

2) Set pattern generator as shown Table 2.

3) Adjust VL102 so that the Noise level is minimized.

System

SECAM-L

Signal Pattern

Color bar

Sound signal

Off

Carrier signal

(Table 2)

* Vertical/Horizontal/E-W (East-West)

Adjustment (LINE SVC 1)

NOTE : These adjustments are already aligned at

the time of manufacture for optimum performance. Readjustment of them should not be necessary unless IC02 (EEPROM) is defective. Because all the information of these adjustment are memorized in that IC.

Adjustment Procedures

1) Tune the TV set to receive a digital circle pattern unless otherwise noted.

2) Press OKbutton on Control Board continuously and OK button on remote controller then you can find On Screen Display. (Refer to the following Fig.3).

3)Press PR+ or PR- button for desirous function adjustment.

4) Press VOL+ or VOL- button for correct picture.

5) Press OK button to memorize all the adjusted data.

6) After finishing adjustment, press TV/AV button on remote controller then TV is changed from SVC mode to normal mode.

[LINE SVC1] 1

VL 43EW 37 VA 21 EP 39 SC 35EC 29 VS 35ET 20 HS 31 50HZ*

CH5

EW--(Horizontal Width)

Adjust to that a digital circle pattern looks like exact circle.

EP--(East-west Parabola)

Adjust so that middle portion of the outermost left and right vertical line looks like parallel with vertical lines of the CPT.

EC--(East-west Corner)

Adjust so that the vertical line at every 4 corners of the screen looks like parallel with the vertical lines of the CPT.

ET--(East-west Trapezium)

Adjust to make the length of top horizontal line same with it of the bottom horizontal line.

* White Balance Adjustment.(LINESVC 2)

NOTE :This adjustment should be performed after screen

voltage adjustment.

1) Tune the TV set to receive an 100% white pattern.

2) Press Number 2 button on remote controller in the SVC Mode (press OK button on control board continuously and OK button on remote controller) then you can find On Screen Display. (Refer to the following Fig.4).

3) Press PSM (RED) button on remote controller. (Standard picture)

4)Press PR+ or PR- button for desirous function adjustment.

5) Adjust VOL+ or VOL- button for GG31. Adjust VOL+ or VOL-button in each status of "RG--"/"BG--"

for X=288

temperature 9000

+_8, Y=295+_8 with color analyzer (color

K).

*: This is only displayed according to

receiving system. PAL/SECAM System : 50Hz

[

NTSC System : 60Hz

Fig. 3

VL--(Vertical Linearity)

Adjust so that the boundary line between upper and lower half is in accord with geometric horizontal center of the CPT.

VA--(Vertical Amplitude)

Adjust so that the circle of a digital circle pattern may be located within the effective screen of the CPT.

SC--(Vertical "S" correction)

Adjust so that all distance between each horizontal lines are to be the same.

VS--(Vertical Shift)

Adjust so that the horizontal center line of a digital circle pattern is in accord with geometric horizontal center of the CPT.

HS--(Horizontal Shift)

Adjust so that the vertical center line of a digital circle pattern isinaccordwithgeometricverticalcenteroftheCPT

[LINE SVC2] 1

RG31 GG31 BG23 DY12*

CH5

Fig. 4

* : Never change this data, this is an important

reference data for TV.

Ref) PAL I/I': DY15

NOTE :If press Number 3 button on the remote controller

in the SVC mode then you can find On Screen Display. (Refer to the following Fig.5).

[LINE SVC3] 1

FP 30 NP 110 SP 23 SV 75

CH5

Fig. 5

*Never change these data, these are important

referencedataforTV

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