LG CG772 (700-069EV) Schematic

SPECIFICATIONS

1. PICTURE TUBE

Size : 17 inch (Flat Square Tube) Gun : In-line DefIection Angle : 90¡ Neck Diameter : 29.1mm Phosphor : P22 Dot Pitch : 0.28mm Low Radiation : TCO-92 or TCO-95

2. SIGNAL

2-1. HORIZONTAL & VERTICAL SYNC

1) Input Voltage Level : Low=0 ~0.7V, High=2.1~ 5.5V

2) Sync Polarity : Positive or Negative

2-2. VIDEO INPUT SIGNAL

1) Voltage Level : 0 ~ 0.7Vp-p a) Color 0, 0 : 0Vp-p b) Color 7, 0 : 0.467Vp-p c) Color 15, 0 : 0.7Vp-p

2) Input Impedance : 75½

3) Video Color : R, G, B Analog

4) Signal Format : Refer to the Timing Chart

2-3. SIGNAL CONNECTOR

15 pin D-Sub Connector

2-4. SCANNING FREQUENCY

Horizontal : 30 ~ 70kHz Vertical : 50~ 160Hz

3. POWER SUPPLY

3-1. POWER RANGE

AC 100 ~ 240V (Free Voltage), 50/60Hz, 2.0A Max.

3-2. POWER CONSUMPTION

4. DISPLAY AREA

4-1. Active Video Area : 315

230mm (12.40" 9.06")

(Available for Full Screen) 4-2. Display Color : Full Colors 4-3. Display Resolution : 1280

1024/60Hz

(Non-Interlace) 4-4. Video Bandwidth : 110MHz

5. ENVIRONMENT

5-1. Operating Temperature: 10¡C ~ 35¡C (50¡F ~ 95¡F)

(Ambient)

5-2. Relative Humidity : 8%~ 80%

(Non-condensing)

5-3. Altitude : 10,000 ft

6. DIMENSIONS (with TILT/SWIVEL)

Width : 415.0mm (16.34 inch) Depth : 459.1mm (18.07 inch) Height : 430.5mm (16.95 inch)

7. WEIGHT (with TILT/SWIVEL)

Net Weight : 17.5kg (38.58 lbs) Gross Weight : 21.0kg (46.30 lbs)

- 2 -

MODE

NORMAL (ON)

STAND-BY

SUSPEND

OFF

H/V SYNC

ON/ON

OFF/ON

ON/OFF

OFF/OFF

POWER CONSUMPTION

less than 110 W

less than 15 W

less than 8 W

LED COLOR

GREEN

ORANGE

- 4 -

MODE

FACTORY PRESET MODE

Resolution

RECALL

H O R

I Z O N T A L

V E

I C A

kHz

µs

MODE 2

31.470

31.776

25.421

6.355

0.636

3.813

1.907

70.000

14.286

12.727

1.559

0.382

0.064

1.114

720

400

70Hz

Yes

MODE 1

37.500

26.667

20.317

6.349

0.508

2.032

3.810

75.000

13.333

12.800

0.533

0.027

0.080

0.427

640

480

75Hz

Yes

MODE 3

46.875

21.333

16.162

5.172

0.323

1.616

3.232

75.000

13.333

12.800

0.533

0.021

0.064

0.448

800

600

75Hz

Yes

MODE 4

53.674

18.631

14.222

4.409

0.569

1.138

2.702

85.061

11.756

11.179

0.578

0.019

0.056

0.503

800

600

85Hz

Yes

MODE 5

60.023

16.660

13.003

3.657

0.203

1.219

2.235

75.029

13.328

12.795

0.533

0.017

0.050

0.466

1024

768

75Hz

Yes

MODE 6

68.677

14.561

10.836

3.725

0.508

1.016

2.201

84.997

11.765

11.183

0.582

0.015

0.044

0.524

1024

768

85Hz

Yes

MODE 7

63.974

15.631

11.797

3.834

0.590

1.180

2.065

60.013

16.663

16.006

0.657

0.016

0.047

0.594

1280

1024

60Hz

Yes

MARK

Sync Polarity

Frequency

Total Period

Video Active Time

Blanking Time

Front Porch

Sync Duration

Back Porch

Sync Polarity

Frequency

Total Period

Video Active Time

Blanking Time

Front Porch

Sync Duration

Back Porch

TIMING CHART

VIDEO

SYNC

CONTROL LOCATIONS

FBT

VIDEO

SW201

VR771

VR901

SW701

VR201

VR151

MAIN

CONTROL

- 9 -

No.

Ref. No.

SW201

VR201

VR771

Ref. No.

VR901

VR151

SW701

Control Function

POWER SWITCH

OSD SELECT/ADJUSTMENT

HIGH-VOLTAGE ADJUSTMENT

Control Function

ADJUSTMENT

TCO ADJUSTMENT

H-RASTER CENTER SW.

Socket

FBT

P201

P402

P502

P706

P701

P302 P301

P601

P901

P304

P303

P702

P401

Signal Cable

VIDEO

MAIN

CONTROL

P151

P152

P153

- 10 -

WIRING DIAGRAM

- 11 -

DISASSEMBLY

1. TILT/SWIVEL REMOVAL

Set the monitor face downward. Pressing the latch , carefully remove the Tilt/Swivel

by pulling it upward.

2. BACK COVER REMOVAL

Remove two screw caps . Remove four screws . Slide the Back Cover away from the Front Cabinet of the monitor.

4. TOTAL CHASSIS ASSEMBLY REMOVAL

Disconnect P902(Degaussing pin), P701, P601 (DY pin), and P501(Tilt pin). Remove two screws from the Total Chassis Assembly. Remove the Total Chassis Assembly.

3. TOP SHIELD REMOVAL

Remove four screws . Remove two screws .

- 12 -

6. BOTTOM BRACKET REMOVAL

Remove three screws . Remove two screws . Remove three screws . Remove the Bottom Bracket.

7. MAIN BOARD ASSEMBLY REMOVAL

Remove three screws . Remove seven screws . Release two latches from the Main Board Assembly.

Bottom Bracket

5. VIDEO BOARD ASSEMBLY REMOVAL

Remove three connectors . Remove CDT ground connector Carefully separate the Video Board Assembly from the CDT neck. Discharge the remaining static electricity by shorting between the Anode Cap and the CDT ground. Disconnect the Anode Cap from the CDT.

Anode Cap

BLOCK DIAGRAM

- 13 -

CONTRAST

BRIGHTNESS

H-SIZE

H-POSITION

V-SIZE

V-POSITION

S-PCC

TRAP

DEGAUSS

RECALL

ADVANCED OPTION

EXIT

COLOR

LANGUAGE

INFORMATION

OSD POSITION

EXIT

MICOM

MC68HC05BD16

(IC401)

OSD

LSC4513P2

(IC311)

SCK

SDT

SCK

SDT

SIGNAL CABLE

V-SYNC

H-SYNC

RGB

DATA LINE

CLOCK LINE

VIDEO

PRE-AMP

(MC13282E)

(IC301)

KA7808

EEPROM

RGB

VIDEO OUTPUT

DISCRETE CIRCUIT

(Q331, 333, 335)

R/G/B

CONTRAST

CDT CUT-OFF

ADJUSTMENT

175V

13V

CDT

13V

70V

12V

-120V

6.3V

SCREEN

FOCUS

D-FOCUS

V-DY

H-DY

High

Voltage

DEGAUSSING

CIRCUIT

DEGAUSSING COIL

RECTIFIER

(D901)

LINE

FILTER

(L901)

POWER INPUT

100-240VAC

(50/60Hz)

PFC

SMPS

TRANS

(T901)

RECTIFIER

6.3V

70V

12V

13V

15V

SMPS CONTROL

KA3842B

& FS14SM-18A

(IC901 & Q911)

175V

O/V, O/C

PROTECTION

DPM CONTROL

STAND-BY, SUSPEND,

POWER OFF

VOLTAGE FEEDBACK

15V

6.3V

ROTATION

CONTROL

TILT COIL

X-RAY

PROTECTION

(IC704)

H/V SYNC PROCESSOR

TDA4854

(IC701)

HIGH

VOLTAGE

OUTPUT

(Q714)

H-SYNC

V-SYNC

SCK,SDT

12V

40V

VERT. OUTPUT

TDA4866

(IC601)

H,V BLANKING

& BRIGHTNESS

CONTROL

175V

D/D CONVERTER

HORIZONTAL

OUTPUT (Q743)

H-LIN &

S-CORRECTION

H-DRV

TCO

D/D

FEEDBACK

ABL &

CONTRAST

DYNAMIC

FOCUS

F.B.T

(T701)

DATA

PWM 6 PORTS

R/G/B/BIAS

KA7805

KA7812

- 14 -

DESCRIPTION OF BLOCK DIAGRAM

1. Line Filter & Associated Circuit.

This is used for suppressing noise of power input line flowing into the monitor or some noise generated in this monitor flowing out through the power input line. That is to say, this circuit prevents interference between the monitor and other electric appliances.

2. Degauss Circuit & Coil.

The degauss circuit consists of the degaussing coil, the PTC(Positive Temperature Coefficient) thermistor (TH902), and the relay(RL901). This circuit eliminates abnormal color of the screen automatically by degaussing the shadow mask in the CDT during turning on the power switch. When you need to degauss in using the monitor, select (DEGAUSS) on the OSD menu.

3. SMPS(Switching Mode Power Supply).

This circuit is working of 90~264V AC(50/60Hz). The operation procedure is as follows:

1) AC input voltage is rectified and smoothed by the bridge diode(D901) and the capacitor(C906).

2) The rectified voltage(DC) is applied to the primary coil of the transformer(T901).

3) The control IC(IC901) generates switching pulse to turn on and off the primary coil of the transformer (T901) repeatedly.

4) Depending on turn ratio of the transformer, the secondary voltages appear at the secondary coils of the transformer(T901).

5) These secondary voltages are rectified by each diode(D951, D952, D955, D956, D957, D958 and D959) and operate other circuit. (horizontal and vertical deflection, video amplifier, ...etc.)

4. Over Voltage Protection Circuit.

This circuit consists of opto-coupler(IC902), shunt regulator diode(IC953), and the associated circuit. If the secondary voltage exceeds the specified voltage, the current of the opto-coupler LED flows excessively. Then, collector current of the opto-coupler flows excessively and stops the oscillation of the control IC(IC901). Consequently, the secondary voltage drops to zero volt.

5. X-ray Protection.

If the high voltage of the FBT reaches up to 30kV (abnormal state), the OP Amp(IC704) pin 7 come to high level and charges at the X-ray protection pin of the TDA4854(IC701) . Then, B-DRV(Pin 6) and H-DRV(Pin 8) function of this IC will be shut down and high voltage will not be generated. (In normal state, the high voltage is about 26kV.)

6. Micom(Microprocessor) Circuit.

The operating procedure of Micom(microprocessor) and its associated circuit is as follows:

1) H and V sync signal is supplied from the signal cable.

2) The Micom(IC401) distinguishes polarity and frequency of H and V sync.

3) The Micom sets operating mode and offers the controlled data. (H-size, H-position, V-size, ... etc.)

4) The controlled data of each mode is stored in itself.

5) User can adjust screen condition by each OSD function. The data of the adjusted condition is stored in EEPROM(IC403).

7. Horizontal and Vertical Oscillation.

This circuit generates the horizontal pulse and the vertical pulse by taking the H and V sync signal. This circuit consists of the TDA4854(IC701) and the associated circuit.

8. Oscillating Circuit for D/D Converter.

This circuit generates the saw-tooth wave which has the horizontal period by taking output of the TDA4854(IC701).

9. D/D (DC to DC) Converter.

This circuit supplies DC voltage to the horizontal deflection output circuit by decreasing DC 175V which is the secondary voltage of the SMPS in accordance with the input horizontal sync signal.

10. Side-Pincushion & Trapezoid Correction Cirucit.

This circuit improves the side-pincushion and the trapezoid distortion of the screen by mixing parabola and saw-tooth wave to output of the horizontal deflection D/D converter which is used for the supply voltage(B+) of the deflection circuit.

11. Horizontal Deflection Output Circuit.

This circuit makes the horizontal deflection by supplying the saw-tooth current to the horizontal deflection yoke.

12. High Voltage Output & FBT(Flyback Transformer).

The high voltage output circuit is used for generating pulse to the primary coil of the FBT(Flyback Transformer (T701)). A boosted voltage(about 26kV) appears at the secondary of the FBT and it is supplied to the anode, focus, and screen voltage of the CDT.

- 15 -

13. H-Linearity Correction Circuit.

This circuit corrects the horizontal linearity for each horizontal sync frequency.

14. H-Raster Centering Circuit.

This circuit makes the back raster stay in the center of the screen by adjusting the SW701.

15. Vertical Output Circuit.

This circuit takes the vertical ramp wave from the TDA4854(IC701) and performs the vertical deflection by supplying the saw-tooth current to the vertical deflection yoke.

16. Dynamic Focus Output Circuit.

This circuit takes the horizontal and the vertical parabola waves from the TDA4854(IC701) and amplifies it to maintain constant focus on center and corners in the screen.

17. V Blanking and Brightness Control.

Blanking circuit eliminates retrace line by supplying negative pulse to the G1 of the CDT. And Brightness circuit is used for control of the screen brightness by changing DC level of the G1.

18. Image Rotation Circuit.

This circuit corrects the tilt of the screen by supplying the image rotation signal to the tilt coil which is attached near the deflection yoke of the CDT.

19. MoirŽ Reduction Circuit.

This circuit reduce interference between the periodical display pattern and the CDT's dot through adjusting vertical scanning lines of the video signal.

20. OSD Circuit.

This circuit is used for performing the OSD(On Screen Display) function. When an user select the OSD Select/Adjustment knob, the adjustment status displays on the screen.

21. Video Pre-Amp Circuit.

This circuit amplifies the analog video signal from 0-0.7V to 0-4V. It is operated by taking the clamp, R, G, B drive and contrast signal from the Micom(IC401).

22. Video Output Amp Circuit.

This circuit amplifies the video signal which comes from the video pre-amp circuit and amplified it to applied the CDT cathode.

23. TCO Circuit

Purpose of this circuit is cancelling low frequency electromagnetic emission of the CDT. Anode of the CDT ripple is sensed by sensor and amplified by inverting OP Amp(IC151). This exactly opposite phase signal emission has effect on cancelling CDTÕs electromagnetic emission.

- 16 -

GENERAL INFORMATION

All adjustment are thoroughly checked and corrected when the monitor leaves the factory, but sometimes several minor adjustment may be required. Adjustment should be following procedure and after warming up for a minimum of 30 minutes.

Alignment appliances and tools.

- IBM compatible PC.

- Programmable Signal Generator. (eg. VG-819 made by Astrodesign Co.)

- E(E)PROM with each mode data saved.

- Alignment Adaptor and Software.

- Digital Voltmeter.

- White Balance Meter.

- Luminance Meter.

- High-voltage Meter.

AUTOMATIC AND MANUAL DEGAUSSING

The degaussing coil is mounted around the CRT so that automatic degaussing when turn on the monitor. But a monitor is moved or faced in a different direction, become poor color purity cause of CRT magnetized, then

press

(DEGAUSSING) on the OSD menu.

ADJUSTMENT PROCEDURE & METHOD

TIMING CHART FOR ADJUSTMENT

- Install the cable for adjustment such as Figure 1 and run

the alignment program on the DOS.

- Set external Brightness and Contrast volume to max position.

1. Adjustment for B+ Voltage.

Display cross hatch pattern at Mode 6. Adjust C951 voltage to 175V 0.5V with VR901.

2. Adjustment for High-Voltage.

Display cross hatch pattern at Mode 6. Adjust FBT Anode voltage to 26kV 0.5kV with

VR771.

3. Adjustment for Horizontal Raster Center.

Display cross hatch pattern at Mode 6. Adjust the raster should be center of the screen with SW701.

4. Check for Horizontal & Vertical OSC Frequency.

Display cross hatch pattern at Mode 8. Check whether screen is synchronized or not. Display cross hatch pattern at Mode 9. Check whether screen is synchronized or not.

5. Adjustment for Factory Mode (Preset Mode).

Display cross hatch pattern at Mode 1. Run alignment program for 700-069EV or CG772. COMMAND START Y(Yes) command. DIST. ADJ. TILT command. Adjust tilt as arrow keys to be the best condition. DIST. ADJ. BALANCE command. Adjust balance of side-pincushion as arrow keys to be the best condition. (between 0~16: 8 set is fit normally.) DIST. ADJ. BALANCE command. Adjust parallelogram as arrow keys to be the best condition. (between 0~16: 8 set is fit normally.) DIST. ADJ. FOS. ADJ Mode No. 1 command. Adjust H-SIZE as arrow keys to 315 2mm. Adjust H-POSITION as arrow keys to center of the screen. Adjust V-SIZE as arrow keys to 230 2mm. Adjust V-POSITION as arrow keys to center of the screen. Adjust S-PCC(Side-Pincushion) as arrow keys to be the best condition. Adjust TRAPEZOID as arrow keys to be the best condition. Display from Mode 2 to Mode 7 and repeat above from number

to .

PRESET EXIT Y(Yes) command.

6. Adjustment for White Balance and Luminance.

Set the White Balance Meter. Press the (DEGAUSSING) on the OSD menu for demagnetization of the CDT. Display color 0,0 pattern at Mode 6. COLOR ADJ. LUMINANCE command of the alignment program. Set Brightness to max position. Set Contrast to max position. COLOR ADJ. BIAS ADJ. COLOR NO. 1 command of the alignment program.

ADJUSTMENT

Sync Polarity

Frequency

Total Period

Video Active Time

Blanking Time

Front Porch

Back Porch

Sync Duration

Resolution

29.99kHz

33.34µs

26.67µs

6.67µs

1.50µs

3.96µs

1.21µs

640

70.03kHz

14.28µs

10.75µs

3.53µs

0.81µs

1.52µs

1.20µs

950

49.99Hz

20.004ms

18.670ms

1.334ms

0.301ms

0.933ms

0.100ms

560

160.25Hz

6.240ms

5.712ms

0.528ms

0.057ms

0.400ms

0.071ms

400

Mode

Horizontal

Mode 8 Mode 9 Mode 8 Mode 9

Vertical

Item

- 17 -

Figure 1. Cable Connection

220

Monitor to be

adjusted

Video

Signal Generator

IBM Compatible PC

Parallel Port

Power inlet (required)

Power LED

ST Switch

Power Select Switch (110V/220V)

Control Line

Not used

RS232C

PARALLEL

V-SYNC

POWER

VGS

MONITOR

V-Sync On/Off Switch (Switch must be ON.)

10 5

4.7K

74LS06

OFF ON

OFF

Set Sub-Bright to max position. Check whether blue color or not at R-BIAS and GBIAS to min position and B-BIAS to 127 position. If it's not blue color, the monitor must repair. Adjust Screen control on the FBT to 0.15 0.05FL of the raster luminance. Adjust R-BIAS and G-BIAS command to x=0.281

0.01 and y=0.311 0.01 on the White Balance Meter with PC arrow keys. Adjust SUB-BRIGHT command to 0.7 0.1FL of the raster luminance. Display color 15,0 box pattern (70 70mm) at Mode 6. DRIVE ADJ No 1. command. Set SUB-CONTRAST to 1/2 (30~40) position. Set B-DRIVE to 170 position at DRIVE of the alignment program.

Adjust R-DRIVE and G-DRIVE command to white balance x=0.281

0.003 and y=0.311 0.003 on the White Balance Meter with PC arrow keys. Adjust SUB-CONTRAST command to 50 1FL of the color 15,0 box pattern (70x70mm) luminance at Mode 6.

Save in COLOR 1. Display color 15,0 full white patten at Mode 6. COLOR ADJ. LUMINANCE ABL command. Adjust ABL to 41 1FL of the luminance. Exit from the program.

7. Adjustment for Focus.

Set the Brightness and Contrast to max position. Display H character in full screen at Mode 6. Adjust two Focus control on the FBT that focus should be the best condition.

- 18 -

TROUBLESHOOTING GUIDE

1. NO POWER

NO POWER

(POWER INDICATOR OFF)

TROUBLE IN D901

TROUBLE IN FUSE (F901)

TROUBLE IN IC901, IC902 Q911, Q921

TROUBLE IN D951, D952, D955, D956, D957, D958, D959

TROUBLE IN

IC951, IC952

CHECK

FUSE OK?

CHECK

C906 VOLTAGE?

(AC120V: 170VDC,

AC220V: 310VDC)

YES

CHECK Q911 DRAIN WAVEFORM

(SQUARE WAVE

COMES OUT?)

CHECK

D951, D952, D955,

D956, D957, D958, D959

VOLTAGE?

- 19 -

2. NO CHARACTER

NO CHARACTER

CHECK

IC301

PIN 9, 17 (8V)?

CHECK

IC301 PIN 2, 4, 6 ?

CHECK

IC301 PIN 15, 19, 22 ?

CHECK

R, G, B CATHODE

VOLTAGE?

CHECK

Q338, Q340, Q342

BASE VOLTAGE ?

TROUBLE IN IC321, P302 13V LINE

TROUBLE IN PC SIGNAL, P301, SIGNAL CABLE

TROUBLE IN IC301

TROUBLE IN Q331~Q336

TROUBLE IN D361, D362, D363, Q361~Q369, Q380, Q383

TROUBLE IN

CDT SOCKET

YES

- 20 -

3. NO RASTER

NO VIDEO

(POWER INDICATOR ON)

CHECK

POWER INDICATOR

GREEN or ORANGE?

CHECK

D795 CATHODE?

(40V)

CHECK

G1 VOLTAGE?

(

10 20V)

TROUBLE IN Q714

TROUBLE IN Q573

TROUBLE IN Q571, Q572

DPM MODE (NO H and/or V-SYNC)

ORANGE

GREEN

YES

- 21 -

4. NO HORIZONTAL DEFLECTION

NO H-DEFLECTION

(ONE VERTICAL LINE)

CHECK

Q743?

CHECK

B+ VOLTAGE

(175V)?

CHECK

Q512 EMITTER

WAVE FORM?

CHECK

T702 PIN 4

B+ VOLTAGE?

TROUBLE IN Q743, D742

TROUBLE IN 175V LINE

TROUBLE IN Q512, Q513

TROUBLE IN Q514

TROUBLE IN L512, T702, P702

YES

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