LG EB770G, E700B Service Manual

COLOR MONIT OR

SER VICE MANUAL

Website:http://biz.LGservice.com

E-mail:http://www.LGEservice.com/techsup.html

CAUTION

BEFORE SERVICING THE UNIT,

READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

MENU SELECT

MODEL: StudioWorks E700B (EB770G-EA)

StudioWorks E700S (EB770G-NA)

E700S (EB770G-NA)

CHASSIS NO. : CA-109

F ACTORY MODEL: EB770G

*( ) ID LABEL Model No.

1. PICTURE TUBE

Size : 17 inch (FCDT)

DefIection Angle : 90°

Neck Diameter : 29.1 mm

Dot Pitch : 0.25 mm

Face Treatment : W-ARASC (Anti-Reflection and

Anti-Static Coating),Anti-Glare

Low Radiation : TCO99, MPR-II

2. SIGNAL

2-1. Horizontal & Vertical Sync

1) Input Voltage Level: Low=0~1.2V, High=2.5~5.5V

2) Sync Polarity : Positive or Negative

2-2. Video Input Signal

1) Voltage Level : 0 ~ 0.7 Vp-p

a) Color 0, 0 : 0 Vp-p

b) Color 7, 0 : 0.467 Vp-p

c) Color 15, 0 : 0.7 Vp-p

2) Input Impedance : 75 Ω

3) Video Color : R, G, B Analog

4) Signal Format : Refer to the Timing Chart

2-3. Signal Connector

15-pin Connector (Attached)

2-4. Scanning Frequency

Horizontal : 30 ~ 70 kHz

Vertical : 50 ~ 160 Hz

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 :

• Max Image Size - 325.1 x 243.8 mm (12.80" x 9.60")

• Preset Image Size - 310 x 230 mm (12.20" x 9.06")

4-2. Display Color : Full Colors

4-3. Display Resolution : 1024 x 768 / 85Hz

(Non-Interlace)

4-4. Video Bandwidth : 110 MHz

5. ENVIRONMENT

5-1. Operating Temperature: 0°C ~ 40°C (32°F ~ 104°F)

(Ambient)

5-2. Relative Humidity : 10%~ 90%

(Non-condensing)

5-3. Altitude : 5,000 m

6. DIMENSIONS (with TILT/SWIVEL)

Width : 400.0 mm (15.74 inch)

Depth : 424.0 mm (16.70 inch)

Height : 395.0 mm (15.55 inch)

7. WEIGHT (with TILT/SWIVEL)

Net Weight : 16.0 kg (35.28 lbs.)

Gross Weight : 18.9 kg (41.67 lbs.)

CONTENTS

- 2 -

SPECIFICATIONS ................................................... 2

SAFETY PRECAUTIONS ........................................ 3

TIMING CHART ....................................................... 4

OPERATING INSTRUCTIONS ................................ 5

WIRING DIAGRAM ................................................. 6

DISASSEMBLY ....................................................... 7

BLOCK DIAGRAM ................................................... 8

DESCRIPTION OF BLOCK DIAGRAM.....................9

ADJUSTMENT ....................................................... 11

TROUBLESHOOTING GUIDE .............................. 13

EXPLODED VIEW...................................................23

EXPLODED VIEW PARTS LIST..............................24

REPLACEMENT PARTS LIST ............................... 25

PIN CONFIGURATION........................................... 30

SCHEMATIC DIAGRAM......................................... 36

PRINTED CIRCUIT BOARD................................... 38

SPECIFICATIONS

MODE

NORMAL (ON)

STAND-BY

SUSPEND

OFF

H/V SYNC

ON/ON

OFF/ON

ON/OFF

OFF/OFF

POWER CONSUMPTION

73 W

less than 15 W

less than 5 W

LED COLOR

GREEN

ORANGE

SAFETY-RELATED COMPONENT WARNING!

There are special components used in this color monitor

which are important for safety. These parts are marked

on the schematic diagram and the replacement

parts list. It is essential that these critical parts should be

replaced with the manufacturer's specified parts to

prevent X-radiation, shock, fire, or other hazards. Do not

modify the original design without obtaining written

permission from manufacturer or you will void the original

parts and labor guarantee.

CAUTION:

No modification of any circuit should be

attempted.

Service work should be performed only after

you are thoroughly familiar with all of the

following safety checks and servicing

guidelines.

SAFETY CHECK

Care should be taken while servicing this color monitor

because of the high voltage used in the deflection circuits.

These voltages are exposed in such areas as the

associated flyback and yoke circuits.

FIRE & SHOCK HAZARD

An isolation transformer must be inserted between the

color monitor and AC power line before servicing the

chassis.

• In servicing, attention must be paid to the original lead

dress specially in the high voltage circuit. If a short

circuit is found, replace all parts which have been

overheated as a result of the short circuit.

• All the protective devices must be reinstalled per the

original design.

• Soldering must be inspected for the cold solder joints,

frayed leads, damaged insulation, solder splashes, or

the sharp points. Be sure to remove all foreign

materials.

IMPLOSION PROTECTION

All used display tubes are equipped with an integral

implosion protection system, but care should be taken to

avoid damage and scratching during installation. Use only

same type display tubes.

X-RADIATION

The only potential source of X-radiation is the picture tube.

However, when the high voltage circuitry is operating

properly there is no possibility of an X-radiation problem.

The basic precaution which must be exercised is keep the

high voltage at the factory recommended level; the normal

high voltage is about 25.5kV in cross-hatch pattern at

68.68kHz. The following steps describe how to measure

the high voltage and how to prevent X-radiation.

Note : It is important to use an accurate high voltage

meter calibrated periodically.

• To measure the high voltage, use a high impedance

high voltage meter, connect (–) to chassis and (+) to

the CDT anode cap.

• Set the brightness control to maximum point at full

white pattern.

• Measure the high voltage. The high voltage meter

should be indicated at the factory recommended level.

• If the meter indication exceeds the maximum level,

immediate service is required to prevent the possibility

of premature component failure.

• To prevent X-radiation possibility, it is essential to use

the specified picture tube.

CAUTION:

Please use only a plastic screwdriver to protect yourself

from shock hazard during service operation.

SAFETY PRECAUTIONS

- 3 -

※ WARNING

The degaussing coil should be connected to pin-connector

(P902) in Main Board, before monitor power on.

- 4 -

TIMING CHART

VIDEO

SYNC

* Mode 1~Mode 4: Basic Mode

H – 37.50 26.67 20.32 6.35 2.03 3.81 0.51

V – 74.99 13.335 12.802 0.533 0.080 0.427 0.026

H + 46.88 21.33 16.16 5.17 1.62 3.23 0.32

V + 75.01 13.331 12.798 0.533 0.064 0.448 0.021

H + 53.68 18.63 14.22 4.41 1.14 2.70 0.57

V + 85.07 11.755 11.178 0.577 0.056 0.503 0.018

H + 68.677 14.561 10.836 3.725 1.016 2.201 0.508

V + 85.00 11.764 11.182 0.582 0.044 0.524 0.014

Mode

H/V

Sort

640x480

75Hz

800x600

85Hz

1024x768

85Hz

800x600

75Hz

<< Dot Clock (MHz), Horizontal Frequency (kHz), Vertical Frequency (Hz), Horizontal etc... (µs), Vertical etc... (ms) >>

Sync

Polarity

Frequency

Total Period

(E)

Video Active

Time (A)

Sync Duration

(D)

Blanking Time

(B)

Back Porch

(F)

Front Porch

(C)

Resolution

1. Power ON/OFF Button

Use

this button to turn the monitor ON or OFF.

2. Power Indicator

This indicator lights up green when the monitor operates

normally; in DPMS (Energy Saving) mode, - stand-by,

suspend, or power off mode - its color changes to

orange, and if abnormal or damaging circuit turns out

orange blink.

3. Select Button

Use this button to enter a selection in the on screen

display.

4. Button

Use these buttons to choose or adjust items in the on

screen display.

5. MENU Button

Use this button to enter or exit the on screen display.

OPERATING INSTRUCTIONS

- 5 -

FRONT VIEW REAR VIEW

AC Power Socket

Signal Connector

ID Label

Front Control Panel

MENU SELECT

Power ON/OFF Button

See Front Control Panel

MENU SELECT

Buttons

MENU Button

Power Button

Power (DPMS) Indicator

SELECT Button

• Brightness and Contrast can be

adjusted directly without entering

the On Screen Display (OSD)

system.

Press the buttons to adjust the settings and then the

MENU button to save all changes. The Brightness and

Contrast functions are also available in the On Screen

Display (OSD) menu.

100

WIRING DIAGRAM

- 6 -

P501

P201

P405

P301

P302

P702

P701

P402

P902

Signal

Cable

Socket

FBT

DISASSEMBLY

- 7 -

(a)

Back Cover

Cabinet

(b)

(c)

Tip

Tip Spec.

A(Width) : 5.0~15.0mm

B(Depth) : 0.6~0.9mm

C(Height) : 12.0mm

1. TILT/SWIVEL & BACK COVER REMOVAL

1) Set the monitor face downward.

2) Pull the latch (a), carefully remove the Tilt/Swivel by pulling it upward.

3) Pressing the latch (b), Back cover by pushing it upward.

4) Release the latch (c).

5) Slide the Back Cover away from the Front Cabinet of the monitor.

2. TOTAL CHASSIS ASSEMBLY REMOVAL

1) Set the monitor face downward.

2) Pressing the latch (a), Main Chassis

by pushing it upward.

(a)

CDT

Please be careful, not to cut pattern.

BLOCK DIAGRAM

- 8 -

OSD

ON/OFF

SELECT

POWER

POWER INPUT

100~240VAC

(50/60Hz)

Line

Filter

Degaussing

Circuit

< OSD Control >

SMPS

TRANS

(T901)

SMPS

CONTROL

(IC901)

DPM

CONTROL

CIRCUIT

Voltage

Regulating

Circuit

80V

50V

15V

6.3V

TILT

Control

Circuit

6.3V

15V

PROM

(IC402)

H / V POSITION

BRIGHTNESS

CONTRAST

H / V SIZE

H CORNER

SPCC

TRAPEZOID

PIN BALANCE

PARALLELOGRAM

ROTATION

RECALL

DEGAUSS

COLOR CURVE

MOIRE

LANGUAGE

VIDEO LEVEL

OSD IC

(IC301)

MTV038-15

H-Sync Sig

V-Sync Sig

C DATA(SDA)

C CLOCK(SCL)

VIDEO

LM1269

PRE-AMP

(IC302)

Signal

Cable

VIDEO

LM2469

LM2480

CUT OFF IC

(IC304)

MAIN AMP

(IC303)

H/V Sync Processor

( IC701 )

TDA4857

V-OUT

( IC601)

TDA4866

H-OUT

( Q706)

H-Linearity

Correction

DC/DC Converter

X-RAY

Protection

Circuit

FBT

( T701 )

Dynamic

Focus

Circuit

Auto

Beam

Limit

Vertical Blanking,

Brightness Control

- 160V

40V

400V

STEP UP

15V

D/D Feed Back

15V

MICOM

(IC401)

SCL / SDA

H/V Sync,

PWM Control

15V

80V

15V

50V

DY CDT

Heater ( 6.3V )

H/V

Sync

Screen(G2)

Dynamic Focus

Static Focus

H.V

R/G/B

Drive/Contrast

Cut-Off

H-DRV

B-DRV

B+

15V

TILT

COIL

DEGAUSSING

COIL

Vout 1

Vout 2

DESCRIPTION OF BLOCK DIAGRAM

- 9 -

1. Line Filter & Associated Circuit.

This is used for suppressing noise of power input line

flowing into the monitor and/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(TH901),

and the relay(RL901). This circuit eliminates abnormal

color of the screen automatically by degaussing the

shadow mask in the CRT 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

diodes (D900) and the capacitor (C908).

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(D941, D942, D951, D961, D962, D971) and operate

other circuit. (horizontal and vertical deflection, video

amplifier, ...etc.)

4. X-ray Protection.

If the high voltage of the FBT reaches up to 29kV (abnormal

state), IC401(MICOM) pin 35 Sensing from FBT directly.

Then MICOM control IC701 (Deflection controller) to stop

Horizontal drive pulse and stop Horizontal Deflection.

5. 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(IC402).

6. 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 TDA4866(IC601) and the

associated circuit.

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

This circuit supplies DC voltage to the horizontal deflection

output circuit by increasing DC 50V which is the

secondary voltage of the SMPS in accordance with the

input horizontal sync signal.

8. 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.

9. Horizontal Deflection Output Circuit.

This circuit makes the horizontal deflection by supplying

the saw-tooth current to the horizontal deflection yoke.

10. 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

secondary of the FBT and it is supplied to the anode,

focus, and screen voltage of the CRT.

11. H-Linearity Correction Circuit.

This circuit corrects the horizontal linearity for each

horizontal sync frequency.

12. Vertical Output Circuit.

This circuit takes the vertical ramp wave from the

TDA4857(IC701) and performs the vertical deflection by

supplying the saw-tooth current to the vertical deflection

yoke.

13. Dynamic Focus Output Circuit.

This circuit takes the horizontal and the vertical parabola

waves from the TDA4857(IC701) and amplifies it to

maintain constant focus on center and corners in the

screen.

- 10 -

14. H& V Blanking and Brightness Control.

Blanking circuit eliminates retrace line by supplying

negative pulse to the G1 of the CRT. And Brightness

circuit is used for control of the screen brightness by

changing DC level of the G1.

15. Image Rotation (Tilt) 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 CRT.

16. 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).

17. Video Output Amp Circuit.

This circuit amplifies the video signal which comes from

the video pre-amp circuit and amplified it to applied the

CRT cathode.

ADJUSTMENT

- 11 -

GENERAL INFORMATION

All adjustment are thoroughly checked and corrected

when the monitor leaves the factory, but sometimes

several adjustments 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.)

- EPROM or EEPROM with saved each mode data.

- 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 CDT 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 CDT magnetized, then

press

DEGAUSS on the OSD menu.

ADJUSTMENT PROCEDURE & METHOD

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

the alignment program on the DOS for IBM compatible PC.

-Set external Brightness and Contrast volume to max position.

1. Adjustment for B

Voltage.

1) Display cross hatch pattern at Mode 4.

2) Check C961 (+) voltage to 50± 0.5Vdc.

2. Adjustment for High-Voltage.

1) Display cross hatch pattern at Mode 4.

2) DIST.ADJ→CTRL PWM → High Voltage Command.

3) Adjust High Voltage to 25.5kV

0.1 kVdc.

4) Press Enter Key.

3. Adjustment for Factory Mode (Preset Mode).

1) Display cross hatch pattern at Mode 1.

2) Run alignment program for EB770G on the IBM

compatible PC.

3) EEPROM → ALL CLEAR → Y(Yes) command.

<Caution> Do not run this procedure unless the

EEPROM is changed. All data in EEPROM (mode

data and color data) will be erased.

4) Power button of the monitor turn off →turn on.

5) COMMAND→PRESET START→Y(Yes) command.

6) DIST. ADJ. → CTRL PWM → TILT command.

7) Adjust tilt as arrow keys to be the best condition.

8) DIST. ADJ. → BALANCE command.

9) Adjust parallelogram as arrow keys to be the best

condition.

10)

Adjust balance of pin-balance as arrow keys to be

the best condition.

11)

DIST. ADJ. → FOS. ADJ command.

12)

Adjust V-SIZE as arrow keys to 230

2mm.

13)

Adjust V-POSITION as arrow keys to center of the

screen.

14)

Adjust H-SIZE as arrow keys to 310

2mm.

15)

Adjust H-POSITION as arrow keys to center of the

screen.

16)

Adjust S-PCC (Side-Pincushion) as arrow keys to be

the best condition.

17)

Adjust TRAPEZOID as arrow keys to be the best

condition.

18)

Save of the Mode 1.

19)

Display from Mode 2 to 4 and repeat above from

number 12) to 19)

20)

PRESET EXIT → Y (Yes) command.

4. Adjustment for White Balance and Luminance.

1) Set the White Balance Meter.

2) Press the DEGAUSS on the OSD menu for

demagnetization of the CDT.

3) COLOR ADJ. → LUMINANCE command of the

alignment program.

4) Set Brightness and Contrast to Max position.

5) Display color 0,0 pattern at Mode 4.

6) COLOR ADJ.→ BIAS ADJ.→ COLOR No. → 1

command of the alignment program.

7) Check whether green color or not at R-BIAS and G-

BIAS to min position and B-BIAS to 127(7F) and

Sub-Brightness to 177(B1) position. Adjust G2

(screen) command to 0.4

0.05FL of the raster

luminance.

8) Adjust R-BIAS and G-BIAS command to x=0.283

0.005 and y=0.298

0.005 on the White Balance

Meter with PC arrow keys.

Adjust SUB-Brightnesscommand to 0.4

0.1FL of the

raster luminance.

10)

Adjust repeat number 8).

11)

After push the “ENTER” key, and “COMMAND →

PRESET EXIT → Y(Yes)” command.

12)

Display color 15,0 full white pattern at Mode 4.

13)

DRIVE ADJ.→ No 1. command.

- 12 -

14)

Set Brightness and Contrast to Max position.

15)

Set SUB-CONTRAST Max 127(7F) (decimal) position.

16)

Set B-DRIVE to 100(64) at DRIVE of the alignment

program.

17-1)

Adjust R-DRIVE and G-DRIVE command to white

balance x=0.283

0.003 and y=0.298

0.003 on the

White Balance Meter with PC arrow keys.

17-2)

Display color 15,0 window pattern (70x70mm) at mode 4.

18)

Adjust SUB-CONTRAST command to 50

2FL .

19)

After push the “ENTER” key, and “COMMAND →

PRESET EXIT → Y(Yes)” command.

20)

Display color 15,0 full white patten at Mode 4.

21)

Set Brightness and Contrast to Max position.

22)

COLOR ADJ. → LUMINANCE → ABL command.

23)

Adjust ABL to 32

1FL of the luminance.

24)

Exit from the program.

5. Input EDID Data.

1) Display color 15,0 cross hatch pattern at Mode 4.

2) EEPROM → Write EDID command and confirm

“EDID Write OK!!” message of monitor.

3) Exit from the alignment program.

4) Power switch OFF/ON for EDID data save.

6. Adjustment for Focus.

1) Set the Brightness and Contrast to max position.

2) Display H character in full screen at Mode 4.

3) Adjust two Focus control on the FBT that focus

should be the best condition.

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