LG T710PG, T710PH 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

Brightview

MODEL: T710P (T710PG-EL)

CHASSIS NO. : CA-1 15

F ACTORY MODEL: T710PG

T710PH (T710PG-HL)

*( ) ID LABEL Model No.

1. PICTURE TUBE

Size : 17 inch (Flat Square Tube) DefIection Angle : 90° Neck Diameter : 29.1mm Diagonal Inch : 16.0” Dot Pitch : 0.25mm Face Treatment : Anti-Glare,

Anti-Static&Anti-Reflection

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

3) Seperated Sync Signal

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 Attached Connector

2-4. Scanning Frequency

Horizontal : 30 ~ 85kHz Vertical : 50 ~ 160Hz

3. POWER SUPPLY

3-1. Power Range

AC 100~240VAC, 50/60Hz 2.0A

3-2. Power Consumption

4. DISPLAY AREA

4-1. Active Video Area :

• Max Image Size - 325.1 x 243.8 mm (12.79" x 9.59")

• Preset Image Size - 315 x 230 mm (12.40" x 9.06") 4-2. Display Color : Full Colors 4-3. Display Resolution : 1280 x 1024 / 75Hz(Max)

(Non-Interlace)

4-4. MTBF : 50,000HRS

5. ENVIRONMENT

5-1. Operating Temperature: 0°C ~ 40°C (Ambient) 5-2. Relative Humidity : 10%~ 90%

(Non-condensing)

5-3. Altitude : 5,000m

6. DIMENSIONS (with TILT/SWIVEL)

Width : 400mm (15.75 inch) Depth : 411mm (16.18 inch) Height : 401mm (15.79 inch)

7. WEIGHT (with TILT/SWIVEL)

Net Weight : 15.7 kg (34.62 lbs.) Gross Weight : 18.3 kg (40.35 lbs.)

CONTENTS

- 2 -

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

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

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

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

CONTROL LOCATIONS ......................................... 6

WIRING DIAGRAM ................................................. 7

BLOCK DIAGRAM ................................................... 9

ADJUSTMENT ...................................................... 12

TROUBLESHOOTING GUIDE .............................. 14

EXPLODED VIEW...................................................24

REPLACEMENT PARTS LIST ............................... 26

PIN CONFIGURATION........................................... 32

SCHEMATIC DIAGRAM......................................... 33

PRINTED CIRCUIT BOARD................................... 35

MODE

MAX

NORMAL

Standby/Suspend

Power OFF

POWER CONSUMPTION

less than 90W less than 73W less than 15W

less than 5W

LED COLOR

GREEN GREEN AMBER AMBER

SPECIFICATIONS

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 26kV. The following steps describe how to measure the high voltage and how to prevent Xradiation.

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 -

- 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

(A)

Video Active

Time (B)

Sync Duration

(E)

Blanking Time

(C)

Back Porch

(F)

Front Porch

(D)

Resolution

- 5 -

OPERATING INSTRUCTIONS

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.

6. Brightview Button(To apply the High brightness)

Use this button to select brightview function. (TEXT/PHOTO/MOVIE/NORMAL)

FRONT VIEW REAR VIEW

AC Power Socket

Signal Connector

ID Label

Front Control Panel

MENU SELECT

Brightview

Power ON/OFF Button

See Front Control Panel

MENU SELECT

Brightview

Buttons

MENU Button

Power Button

Power (DPMS) Indicator

SELECT Button

Brightiew 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

CONTROL LOCATIONS

- 6 -

VR701 : High Voltage Regulation off-set Voltage Adjustment(4.6V)

VR901: B Adjustment

(50V Line)

WIRING DIAGRAM

- 7 -

P501

P201

P405

P904

P905

P301

P302

P702

P701

P402

P902

Signal Cable

AC Socket

FBT

- 8 -

DISASSEMBLY

1. TILT/SWIVEL & BACK COVER REMOVAL

1) Set the monitor face downward.

2) 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). (See Tip Spec.)

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

Tip Spec.

A(Width) : 5.0~15.0mm B(Depth) : 0.6~0.9mm C(Height) : 12.0mm

Back Cover

(c)

Cabinet

(a)

Tip

(b)

BLOCK DIAGRAM

- 9 -

Power Input

90~264VAC

(50/60Hz)

Line

Filter

Degaussing

Circuit

[ OSD Control ]

SMPS

Control

(IC901)

TILT

Control

Circuit

6.3V

15V

PROM

(IC402)

OSD IC

(IC301)

H-Sync Signal

V-Sync Signal

C DAT A(SDA)

C CLOCK(SCL)

VIDEO

Pre-A mp

(IC302)

Signal

Cable

RGB

VIDEO

Main Amp

(IC303)

CUT OFF

Control

(IC304)

H/V Sync Processor

( IC701)

V-out

( IC601)

H-Linearity

Correction

X-RAY

Protection

Circuit

Dynamic

Focus

Circuit

Vertical blanking

- 160V

40V

15V

MICOM

(IC401)

SCL / SDA

H/V Sync.

PWM Control Signal

15V

50V

DY CDT

Heater ( 6.3V )

H/V

Sync

H.V

R/G/B

DRV/BIA S

Contrast

Brightness

H-Drive

B-Drive

15V

BRIGHTNESS/CONTRAST

H / V POSITION

H / V SIZE

SPCC

TRAPEZOID

PIN BALANCE

PARALLELOGRA

ROTATION

RECALL

DEGAUSS

COLOR CURVE

MOIRE

LANGUAGE

TOP/BOTTOM CORNER

INFORMATION

EXIT

DPM

Control

Circuit

400V

6.3V

15V

80V

Degaus sing

Coil

Dynamic Focus Static Focus

TILT

Coil

15V

50V

Auto

Beam

Limit

DC/DC Converter

FBT

( T701 )

80V

SMPS

Trans

(T901)

H-OUT

(Q706)

Voltage

Regulating

Circuit

Vout 1

Vout 2

B+

D/D Feed Bac

Step-up

DESCRIPTION OF BLOCK DIAGRAM

- 10 -

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 eliminated abnormal color of the screen automatically by degaussing the shadow mask in the CRT during turning on the powerswitch.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(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 power control FET(Q901) the primary coil of the transformer(T901) is turned on and off repeatedly by Q901.

4)Depending on turn ratio of the transformer, the secondary voltage 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 pulses 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 signa 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 DC50V which is the secondary voltage of the SMPS in accordance with the input horizontal sync signal.

8.Side-Pincushion & Trapezoid Correction Circuit.

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 TDA4841(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 vertical parabola waves from the TDA4841(IC701) and amplifiers it to maintain constant focus on center and corners in the screen.

14.

H&V Blanking and Brightness Control.

Blanking circuit eliminates retrace line by supplying negative pulse to G1 of CRT.And Brightness control uses the IIC line , changes the cut-off DC Level.

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.

- 11 -

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.

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