LG NC5AA Diagram

ADJUSTMENT INSTRUCTION

These instructions are applied to only NC-5AA chassis.

Notes

1.So this is a hot chassis, you must be careful, and be caution not to touch 1st and 2nd concurrently.

2.Adjustment must be done in the correct order.

3.Power supply of a SET which is adjusted is 100~240V A.C./50~60Hz.

4.The receiver must be operated for about 30 minutes proir to the adjustment.

CONTENTS

1) VIF, AFT and SIF Adjustment

2) Sound Multiplex Adjustment

3) FOCUS Adjustment

4) AGC Adjustment

4)-1 Picture AGC Adjustment

5) V-Size and V-Center Adjustment

6) Horizontal Size, Center and Side Pincushion Adjustment

7) Purity and Convergence Adjustment

8) White Balance Adjustment

9) SUB-Bright Adjustment

10) Vertical Center Adjustment

11) Horizontal Center Adjustment

1. VCO and AFT Adjustment

This Adjustment must be applied only to PCB Assy.

1.1. Necessary Instruments

1) Sweamer Generator : can sweep 35MHz~55MHz(over

120dBu)

2) PLUG in Unit : With PIF(45.75MHz), SIF(41.25MHz) Marker

3) Alignment Scope : X-Y mode, 10mV~20V Variable

4) D.C. Power Supply : 0~12V Variable

5) D.C. Power Supply : 13.5V±0.2V (over 300mA)

6) Digital Multimeter

1.2. Preliminary Steps

1) Connect the output of Sweamer Generator like <Fig 1>.

Here, set the output of Sweamer Gen. to 100±5dBu.

POWER

SUPPLY

TUNER

SWEEMAR

GENERATOR

ALIGNMENT

SCOPE

TP2

SAW

FILTER

470/0.5W

7.5V

TP11

C122

C508

IC501

LA7674

R591

TP12

L501

VCO COIL

R520

C521

R518

TP4

R507

L506

AFT COIL

Q503

R517

L503

Z502

TP3

L502

12.5V

POWER

SUPPLY

D502

2) Connect H.Scope and Pulse output of Sweamer Generator to H.Input and Marker input of Alignment Scope, respectively.

3) Apply AGC Voltage(D.C.) to TP11 of IC201.(7.5±0.05V)

4) Apply B+ of IC201 to TP12 of R591.(12.0±0.1V)

5) Set VR526(AGC Adjustment) to mechanical center.

1.3. Adjustment

A. VCO

1) Set the vertical range of Alignment Scope to 1V/DIV and

CAL position, and, by applying D.C. 0~9V, do DC

Calibration to place D.C 4.5V point of waveform to center of Screen.

2) Connect the Input terminal of Alignment Scope to TP3(Video Detection Output), and set Vertical Variable Switch to CAL position.

3) Apply AGC Voltage to TP11 of IC201 through 470§to be

7.5±0.05V

4) Adjust L501 so that BEAT appears on 45.75MHz Marker like <Fig 2> If not, adjust again after attenuating output 10

~20dBu.

42.75

B. AFT

1) Connect the Input of Alignment Scope to TP4 with keeping DC voltage of 2pin of IC201.

2) Keep the output of Sweamer Generator 100±5dBu.

3) Adjust L506 so that waveform of Alignment Scope to be that of <Fig 3>.

4) Adjust Vertical Volume of Alignment Scope to place DC level of waveform to center (4.5V) and 45.75MHz Marker to

7.5V¡0.5V.

AFT

2. SIF Adjustment

VCO

2.1. Necessary Instruments

1) Sweamer Generator : can sweep 3~6MHz

2) Plug In Unit : with 4.5MHz Marker

3) Alignment Scope : X-Y mode(can measurable 10mV~

20Vp-p)

4) DC Power Supply : 13.5V, over 300mA

5) DC Power Supply : 0~12V variable

f (MHz)

45.0 47.25

45.75MHz (Turn L105 so that the position of Beat is same with 45.75MHz Marker)

45.75 MARKER

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2.2. Adjustment

1) Connect Sweamer Generator and Alignment Scope the same method of VIF adjustment.

2) Connect the output of Sweamer Generator to TP5 like <Fig 4 >.

3) Connect the Input of Alignment Scope to TP6.

4) Apply AGC voltage of IC201 to TP11(7.5±0.05V).

5) Apply B+ of IC201 to TP12.

6) Adjust L502 S-shaped waveform of Alignment Scope to be that of <Fig 5>.

Adjust (A=B)

Because 4.5MHz Marker doesn’t with horizontal line, apply (a) marker(4.5MHz) to be the center of (b), (c)Markers.

100% WHITE

75% WHITE

DC POWER

SUPPLY

DC 12V

TP13

R591

TP12

DC POWER

SUPPLY

DC 12.5V

12.5V

POWER

SUPPLY

A = B

POWER

ALIGNMENT

SCOPE

TP6

7.5V

TP11

C508

IC501

LA7674

SWEEMAR

GENERATOR

TP5

C515

C516

Z501

SUPPLY

C509

470/0.5W

L502

SIF COIL

R591

TP12

C206

ZD201

PATTERN

A/V IN

VIDEO

SOUND

R609

GENERATOR

TP8

R210

Q206

IC202

C204

C507

Q603

IC601

COLD

8 7

HOT

VR202

Q201

R618

Q601

Q202

L201

C510

OSCILLOSCOPE

C201

6.0MHz

VIDEO

SOUND

TP10

3.3 Adjustment

Adjust VR202 to get Luminance signal(Color Bar) level like below. ( Refer to <Fig 6> )

1) White 100% modulated 1.78±0.1Vp-p

2) White 75% modulated 1.46±0.1Vp-p

4. Automatic Gain Control(AGC) Adjustment

4.1Turn on a SET and receive Digital Pattern of 65¡1dB through

(b)

(a)

4.5 MARKER

75§Ant. terminal.

4.2 Connect DMM(Digital Multi-Meter) to J27.

4.3 Adjust VR101 to read 5.7±0.05V of DMM. (Where, you can set proper AGC voltage according to signal

condition.)

(c)

3. Composite Video Signal Adjustment

3.1.Necessary Instruments

1) Pattern Generator : PM5518(PHILIPS) or Equivalents 7 Step Color Bar Pattern with 75§out

2) Oscilloscope : VP-5650A or Equivalents can measure over 1.0Vp-p Vertical Freq. : over 4MHz

3) DC Power Supply : 12.2±0.2V/400mA 2EA

3.2. Preliminary Steps

1) Connect the output of Pattern Generator to TP8 like <Fig 7>.

Where, the output of Pattern Generator is 1.0Vp-p.(Point

position “A”)

2) Connect DC Power Supply to TP12 and TP13. Where, devide Ground of TP12 and TP13(HOT/COLD).

3) Connect probe to TP10(point “D”).

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5. Purity and Convergence Adjustment

This adjustment should be made when a complete re-alignment is required or a new picture tube is installed.

5.1 Purity Adjustment

5.1.1 Necessary instruments and Preliminary steps

1) Pattern Generator : 216/1 or Equivalents

2) Degauss CPT and Cabinet with Degaussing coil.

3) Maximize Contrast level.

4) Pre-adjust the DY.

5.1.2 Adjustment

1) Receive Raster signal(Red).

2) Push the DY to get Picture like <Fig 8>.

3) Adjust 2-pole magnet to place RED center of screen orthogonally.

4) Pre-fix 2-pole magnet after adjustment with Lock Ring.

,,,,,

5) Pull the DY back slowly to get uniformly RED picture and fix it.

5.2 Convergence Adjustment

5.2.1 Necessary Instruments

1) Pattern Generator : 216/1 or Equivalents

2) Degaussing coil

5.2.2 Preliminary Steps

1) Do this adjustment after operating the SET more than 30 minutes.

2) Degauss CPT and Cabinet with Degaussing coil.

3) Receive Cross hatch pattern.

4) Adjust Contrast and Bright properly.

5) Untighten half-fixed Magnet Assy lock ring

5.2.3 Adjustment

A. Center(Static) Convergence Adjustment

1) Unify Red and Blue vertical lines at center of screen by varying the angle of two tabs of 4-pole magnet.

2) Rotate tab with sustaining the angle of item 1) and unify Red and Blue vertical lines at center of screen.

3) Unify Red,Blue and Green vertical lines by adjusting two tab2 of 6-pole magnet.

4) Rotate tab with sustaining the angle of item 3) and unify Red,Blue and Green vertical lines.

5) To get more detail adjustment repeat 1),2) with remembering changes of Red,Blue and Green.

6) Fix magnet assy lock ring.

B. Dynamic Convergence Adjustment

1) Prepare bonded rubber wedge.

2) Adhere rubber wedge to “A” part halfly.

(Don’t remove paper of bonding part.)

3) Move the DY every direction to get best convergence in every corner.

4) Adhere rubber wedge to bottom of CPT.(Refer <Fig 9>).

5) After checking the locatons of 3 wedges and check Convergence.

6) Paint white lacquer on DY fixing nut and magnet.

ADHESIVE TAPE

RUBBER WEDGES

TEMPORARY MOUNTING

DEFLECTION YOKE

PURITY &CONVERGENCE MAGNET ASSEMBLY

,,,

PURITY MAGNET

4-POLE

GLASS CLOTH TAPE

6-POLE

6. White Balance

6.1 White Balance Adjustment

6.1.1 Necessary Instrument

1) White BAlance Meter

6.1.2 Preliminary Steps

1) Do this adjustment after operating the SET more than 30 minutes.

2) Receive Standard White pattern.

3) Adjust under “APC ON” condition.

4) Turn Screen VR CCW.

5) Set Red driver(VR571) and Blue driver(VR572) to mechanical center.

6) Set Red Bias(VR574) ,Blue Bias(VR575) and Green Bias(VR573) to 1/3 point to Clock-wise from full CCW.

7) Set SVC SW to “SVC” to get Horizontal line.

6.1.3 Adjustment

1) Turn screen VR slowly to see first horizontal line on screen

2) Make horizontal line white with 2 Bias VRs which aren’t displayed in 1).

3) Vary screen VR to get very dim horizontal line.

4) Set SVC SW to “Normal” position.

5) Receive adjustment signal-White in upper and Black in Lower.

6) Vary Red driver(VR571) and Blue driver(VR572) to get White screen in White.

7) Vary Bias and Drivers to get the best screen in White and Black.

8) Check adjustment condition with White Balance Meter.

9) Refer below for Adjustment

Color Temperature

10,000K

High Light : 40fl Low Right : 4fl

0.281

0.288

7. Focus Adjustment

1) Receive Digital pattern.

2) Set screen conditon to “APC ON”.

3) Turn Focus VR to get the best condition in center and every corner.

8. Sub-Bright Adjustment

1) Receive Digital pattern.

2) Do this adjustment after operating the SET more than 30 minutes.

3) After selecting Sub-mode with SVC Remocon and vary to distinguish 4 and 5 step of Gray scale.

9. Vertical Size Adjustment

1) Receive Digital pattern and set screen conditon to “APC ON”.

2) Vary Vertical Size adjustment VR(VR301) to reach inner circle of large circle to edge of frame.

30¡£

RUBBER WEDGES LOCATION

30¡£

DEFLECTION YOKE

ADHESIVE

10. Vertical Center Adjustment

1) Receive Digital pattern and set screen condition to “APC ON”.

2) Adjust the center of screen with SVC SW(SW301) to place center.

11. Horizontal Center Adjustment

1) Receive Digital pattern and set screen condition to “APC ON”.

2) Adjust the center of screen with VR505 to place center.

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