LG NC55AA Diagram

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BLOCK DIAGRM

TUNER

HOT

COLD

TU100

IC2

D801

IC301

IC801

RL801

D/G

COIL

IC1

PA1

5V 12V 33V

LOCK CLOCK DATA CS

2 5

39 41

SDA/SCL

R, G, B, Ys

Q806

Q10

Q401

Q402

1877

H. D. T

Q805

TMP67CC31

IC501

8 9

50 51 45 46

T402

FBT

23 28

LA7674

SMPS TRANS

IC601

PRE-AMP

EEPROM

12V

R-Y, B-Y, G-Y

24V

180V

STR50092K

PWR

Q11

FBP

FROM FBT

H.Vcc of

IC501

AFT

Z101

VIF

SIF

VCO

AFT

SHARP BRI COLOR TINT CONT

PRE-AMP.

Q102

SIF-IN

DET-OUT

SFE4.5

TPS4.5

AUDIO IN VIDEO IN

2 12

IC602

CPT

1 4

T403

-Y

TDA

2006

IC202

Q208

Q603

3 2

9 5

HT 24V 12V FBP

B+

COL

CPT

TO IC1 TO CPT TO T403

CPT

JA001

PCB

D/G

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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