LG M2294A Service Manual

LCD MONITOR TV

SERVICE MANUAL

CAUTION

BEFORE SERVICING THE CHASSIS, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

CHASSIS : LN73A

MODEL : M2294A

M2294A-PMJ

North/Latin America http://aic.lgservice.com Europe/Africa http://eic.lgservice.com Asia/Oceania http://biz.lgservice.com

Internal Use Only

LGE Internal Use Only

- 2 -

CONTENTS

CONTENTS .............................................................................................. 2

PRECAUTIONS .........................................................................................3

SPECIFICATION ........................................................................................6

ADJUSTMENT INSTRUCTION ...............................................................14

TROUBLE SHOOTING ............................................................................17

BLOCK DIAGRAM...................................................................................23

DESCRIPION OF BLOCK DIAGRAM .....................................................24

RIPS BOARD BLOCK DIAGRAM ...........................................................25

EXPLODED VIEW .................................................................................. 26

SVC. SHEET ...............................................................................................

LGE Internal Use Only

- 3 -

SAFETY PRECAUTIONS

Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts are identified by in the Schematic Diagram and Exploded View. It is essential that these special safety parts should be replaced with the same components as recommended in this manual to prevent Shock, Fire, or other Hazards. Do not modify the original design without permission of manufacturer.

General Guidance

An isolation Transformer should always be used during the servicing of a receiver whose chassis is not isolated from the AC power line. Use a transformer of adequate power rating as this protects the technician from accidents resulting in personal injury from electrical shocks.

It will also protect the receiver and it's components from being damaged by accidental shorts of the circuitry that may be inadvertently introduced during the service operation.

If any fuse (or Fusible Resistor) in this TV receiver is blown, replace it with the specified.

When replacing a high wattage resistor (Oxide Metal Film Resistor, over 1W), keep the resistor 10mm away from PCB.

Keep wires away from high voltage or high temperature parts.

Before returning the receiver to the customer,

always perform an AC leakage current check on the exposed metallic parts of the cabinet, such as antennas, terminals, etc., to be sure the set is safe to operate without damage of electrical shock.

Leakage Current Cold Check(Antenna Cold Check)

With the instrument AC plug removed from AC source, connect an electrical jumper across the two AC plug prongs. Place the AC switch in the on position, connect one lead of ohm-meter to the AC plug prongs tied together and touch other ohm-meter lead in turn to each exposed metallic parts such as antenna terminals, phone jacks, etc. If the exposed metallic part has a return path to the chassis, the measured resistance should be between 1MΩ and 5.2MΩ. When the exposed metal has no return path to the chassis the reading must be infinite. An other abnormality exists that must be corrected before the receiver is returned to the customer.

Leakage Current Hot Check (See below Figure)

Plug the AC cord directly into the AC outlet.

Do not use a line Isolation Transformer during this check.

Connect 1.5K/10watt resistor in parallel with a 0.15uF capacitor between a known good earth ground (Water Pipe, Conduit, etc.) and the exposed metallic parts. Measure the AC voltage across the resistor using AC voltmeter with 1000 ohms/volt or more sensitivity. Reverse plug the AC cord into the AC outlet and repeat AC voltage measurements for each exposed metallic part. Any voltage measured must not exceed 0.75 volt RMS which is corresponds to

0.5mA. In case any measurement is out of the limits specified, there is possibility of shock hazard and the set must be checked and repaired before it is returned to the customer.

Leakage Current Hot Check circuit

1.5 Kohm/10W

AC Volt-meter

When 25A is impressed between Earth and 2 Grond

* Base on Adjustment standard

Good Earth Ground

To Instrument's

such as WATER PIPE, CONDUIT etc.

exposed METALLIC PARTS

for 1 second, Resistance must be less than 0.1

IMPORTANT SAFETY NOTICE

0.15uF

Ω

LGE Internal Use Only

- 4 -

CAUTION: Before servicing receivers covered by this service manual and its supplements and addenda, read and follow the

SAFETY PRECAUTIONS on page 3 of this publication. NOTE: If unforeseen circumstances create conflict between the

following servicing precautions and any of the safety precautions on page 3 of this publication, always follow the safety precautions. Remember: Safety First.

General Servicing Precautions

1. Always unplug the receiver AC power cord from the AC power source before; a. Removing or reinstalling any component, circuit board

module or any other receiver assembly.

b. Disconnecting or reconnecting any receiver electrical plug or

other electrical connection.

c. Connecting a test substitute in parallel with an electrolytic

capacitor in the receiver. CAUTION: A wrong part substitution or incorrect polarity installation of electrolytic capacitors may result in an explosion hazard.

2. Test high voltage only by measuring it with an appropriate high voltage meter or other voltage measuring device (DVM, FETVOM, etc) equipped with a suitable high voltage probe. Do not test high voltage by "drawing an arc".

3. Do not spray chemicals on or near this receiver or any of its assemblies.

4. Unless specified otherwise in this service manual, clean electrical contacts only by applying the following mixture to the contacts with a pipe cleaner, cotton-tipped stick or comparable non-abrasive applicator; 10% (by volume) Acetone and 90% (by volume) isopropyl alcohol (90%-99% strength) CAUTION: This is a flammable mixture. Unless specified otherwise in this service manual, lubrication of contacts in not required.

5. Do not defeat any plug/socket B+ voltage interlocks with which receivers covered by this service manual might be equipped.

6. Do not apply AC power to this instrument and/or any of its electrical assemblies unless all solid-state device heat sinks are correctly installed.

7. Always connect the test receiver ground lead to the receiver chassis ground before connecting the test receiver positive lead. Always remove the test receiver ground lead last.

8. Use with this receiver only the test fixtures specified in this

service manual.

CAUTION: Do not connect the test fixture ground strap to any heat sink in this receiver.

Electrostatically Sensitive (ES) Devices

Some semiconductor (solid-state) devices can be damaged easily by static electricity. Such components commonly are called Electrostatically Sensitive (ES) Devices. Examples of typical ES devices are integrated circuits and some field-effect transistors and semiconductor "chip" components. The following techniques should be used to help reduce the incidence of component damage caused by static by static electricity.

1. Immediately before handling any semiconductor component or semiconductor-equipped assembly, drain off any electrostatic charge on your body by touching a known earth ground. Alternatively, obtain and wear a commercially available discharging wrist strap device, which should be removed to prevent potential shock reasons prior to applying power to the

unit under test.

2. After removing an electrical assembly equipped with ES devices, place the assembly on a conductive surface such as aluminum foil, to prevent electrostatic charge buildup or exposure of the assembly.

3. Use only a grounded-tip soldering iron to solder or unsolder ES devices.

4. Use only an anti-static type solder removal device. Some solder removal devices not classified as "anti-static" can generate electrical charges sufficient to damage ES devices.

5. Do not use freon-propelled chemicals. These can generate electrical charges sufficient to damage ES devices.

6. Do not remove a replacement ES device from its protective package until immediately before you are ready to install it. (Most replacement ES devices are packaged with leads electrically shorted together by conductive foam, aluminum foil or comparable conductive material).

7. Immediately before removing the protective material from the leads of a replacement ES device, touch the protective material to the chassis or circuit assembly into which the device will be installed. CAUTION: Be sure no power is applied to the chassis or circuit, and observe all other safety precautions.

8. Minimize bodily motions when handling unpackaged replacement ES devices. (Otherwise harmless motion such as the brushing together of your clothes fabric or the lifting of your foot from a carpeted floor can generate static electricity sufficient to damage an ES device.)

General Soldering Guidelines

1. Use a grounded-tip, low-wattage soldering iron and appropriate tip size and shape that will maintain tip temperature within the range or 500ºF to 600ºF.

2. Use an appropriate gauge of RMA resin-core solder composed of 60 parts tin/40 parts lead.

3. Keep the soldering iron tip clean and well tinned.

4. Thoroughly clean the surfaces to be soldered. Use a mall wirebristle (0.5 inch, or 1.25cm) brush with a metal handle. Do not use freon-propelled spray-on cleaners.

5. Use the following unsoldering technique a. Allow the soldering iron tip to reach normal temperature.

(500ºF to 600ºF) b. Heat the component lead until the solder melts. c. Quickly draw the melted solder with an anti-static, suction-

type solder removal device or with solder braid.

CAUTION: Work quickly to avoid overheating the circuit

board printed foil.

6. Use the following soldering technique. a. Allow the soldering iron tip to reach a normal temperature

(500ºF to 600ºF)

b. First, hold the soldering iron tip and solder the strand against

the component lead until the solder melts.

c. Quickly move the soldering iron tip to the junction of the

component lead and the printed circuit foil, and hold it there only until the solder flows onto and around both the component lead and the foil. CAUTION: Work quickly to avoid overheating the circuit board printed foil.

d. Closely inspect the solder area and remove any excess or

splashed solder with a small wire-bristle brush.

SERVICING PRECAUTIONS

LGE Internal Use Only

- 5 -

IC Remove/Replacement

Some chassis circuit boards have slotted holes (oblong) through which the IC leads are inserted and then bent flat against the circuit foil. When holes are the slotted type, the following technique should be used to remove and replace the IC. When working with boards using the familiar round hole, use the standard technique as outlined in paragraphs 5 and 6 above.

Removal

1. Desolder and straighten each IC lead in one operation by gently prying up on the lead with the soldering iron tip as the solder melts.

2. Draw away the melted solder with an anti-static suction-type solder removal device (or with solder braid) before removing the IC.

Replacement

1. Carefully insert the replacement IC in the circuit board.

2. Carefully bend each IC lead against the circuit foil pad and solder it.

3. Clean the soldered areas with a small wire-bristle brush. (It is not necessary to reapply acrylic coating to the areas).

"Small-Signal" Discrete Transistor Removal/Replacement

1. Remove the defective transistor by clipping its leads as close as possible to the component body.

2. Bend into a "U" shape the end of each of three leads remaining on the circuit board.

3. Bend into a "U" shape the replacement transistor leads.

4. Connect the replacement transistor leads to the corresponding leads extending from the circuit board and crimp the "U" with long nose pliers to insure metal to metal contact then solder each connection.

Power Output, Transistor Device Removal/Replacement

1. Heat and remove all solder from around the transistor leads.

2. Remove the heat sink mounting screw (if so equipped).

3. Carefully remove the transistor from the heat sink of the circuit board.

4. Insert new transistor in the circuit board.

5. Solder each transistor lead, and clip off excess lead.

6. Replace heat sink.

Diode Removal/Replacement

1. Remove defective diode by clipping its leads as close as possible to diode body.

2. Bend the two remaining leads perpendicular y to the circuit board.

3. Observing diode polarity, wrap each lead of the new diode around the corresponding lead on the circuit board.

4. Securely crimp each connection and solder it.

5. Inspect (on the circuit board copper side) the solder joints of the two "original" leads. If they are not shiny, reheat them and if necessary, apply additional solder.

Fuse and Conventional Resistor Removal/Replacement

1. Clip each fuse or resistor lead at top of the circuit board hollow stake.

2. Securely crimp the leads of replacement component around notch at stake top.

3. Solder the connections. CAUTION: Maintain original spacing between the replaced component and adjacent components and the circuit board to prevent excessive component temperatures.

Circuit Board Foil Repair

Excessive heat applied to the copper foil of any printed circuit board will weaken the adhesive that bonds the foil to the circuit board causing the foil to separate from or "lift-off" the board. The following guidelines and procedures should be followed whenever this condition is encountered.

At IC Connections

To repair a defective copper pattern at IC connections use the following procedure to install a jumper wire on the copper pattern side of the circuit board. (Use this technique only on IC connections).

1. Carefully remove the damaged copper pattern with a sharp knife. (Remove only as much copper as absolutely necessary).

2. carefully scratch away the solder resist and acrylic coating (if used) from the end of the remaining copper pattern.

3. Bend a small "U" in one end of a small gauge jumper wire and carefully crimp it around the IC pin. Solder the IC connection.

4. Route the jumper wire along the path of the out-away copper pattern and let it overlap the previously scraped end of the good copper pattern. Solder the overlapped area and clip off any excess jumper wire.

At Other Connections

Use the following technique to repair the defective copper pattern at connections other than IC Pins. This technique involves the installation of a jumper wire on the component side of the circuit board.

1. Remove the defective copper pattern with a sharp knife. Remove at least 1/4 inch of copper, to ensure that a hazardous condition will not exist if the jumper wire opens.

2. Trace along the copper pattern from both sides of the pattern break and locate the nearest component that is directly connected to the affected copper pattern.

3. Connect insulated 20-gauge jumper wire from the lead of the nearest component on one side of the pattern break to the lead of the nearest component on the other side. Carefully crimp and solder the connections. CAUTION: Be sure the insulated jumper wire is dressed so the it does not touch components or sharp edges.

LGE Internal Use Only

- 6 -

SPECIFICATION

NOTE : Specifications and others are subject to change without notice for improvement

4. Module Specification

4.1 M2294A-PMJ : LM220WE1-TLE1

1. Application Range.

This spec sheet is applied to the 22” Wide Monitor TV used LN73A chassis.

2. Specification

Each part is tested as below without special appointment

2.1 Power Voltage : Standard input voltage (100~240V@ 50/60Hz)

• Standard Voltage of each products is marked by models

2.4 Specification and performance of each parts are followed each drawing and specification by part number in accordance with BOM .

2.5 The receiver must be operated for about 20 minutes prior to the adjustment.

3. Test method

3.1 Performance : LGE test method followed.

3.2 Demanded other specification

3.3 Safety : CE, IEC specification EMC : CE, IEC

No Item Specification Unit Remark

1 Type TFT Color LCD Module

2 Active Display area 473.76 (H) x 296.1 (V) mm

3 Outline Dimension 493.7(H) x 320.1(V) x 16.5(D) mm Typ.

4 Pixel Pitch 0.282mm(H) x 0.282mm(V) x RGB mm

5 Color arrangement RGB vertical Stripe

6 Color Depth 16.7M color

7 Electrical Interface LVDS

8 Surface Treatment Hard coating(3H) & Anti-glare(Haze 25)

9 Operating Mode Normally White

10 Backlight Unit 4 CCFL(4 lamps)

11 Response Time 2.6ms(Typ.), 7.4ms(Max.) ms Typ.

5. General Specification

5.1 TV

- 7 -

LGE Internal Use Only

No Item Specification Remarks

1 Video input applicable system NTSC, NTSC 4.43

2 Receivable Broadcasting System PAL N/M, NTSC M BRAZIL

3 RF Input Channel VHF : 2~13

UHF : 14~69

CATV : 1~125 PAL N/M, NTSC

4 Input Voltage AC 100 ~ 240 V, 50Hz/60Hz

5 Market BRAZIL

6 Tuning System FS PAL N/M, NTSC

7 Operating Environment Temp : 10 ∞C ~ 35 ∞C

Humidity : 20 % ~ 80 %

8 Storage Environment Temp : -10 ∞C ~ 60 ∞C non condensing

Humidity : 5 % ~ 90 % non condensing

9 Display LCD Module

5.2 RGB / DVI

No Item Specification Remarks

1 Supported Sync. Type Separate Sync., Digital

2 Operating Frequency Analog Horizontal 28 ~ 83kHz

Vertical 56 ~ 75 Hz

Digital Horizontal 28 ~ 83kHz

Vertical 56 ~ 75 Hz

3 Resolution Analog Max. 1680x1050 @ 60Hz

Recommand 1680x1050 @ 60Hz

Digital Max. 1680x1050 @ 60Hz

Recommand 1680x1050 @ 60Hz

4 Input Voltage Voltage :100 – 240 Vac, 50 or 60Hz

5 Inrush Current Cold Start : 50 A Hot : 120 A

6 Operating Condition Sync (H/V) Video LED Wattage

Power S/W On On mode On/On Active Blue 55W(Max) Test condition:

On/On Active Blue 50W (Typ) -RGB-PC input with Max Resolution

Sleep mode Off/On

Off Amber 1W

-The others condition is to be default

On/Off

-Power supply (220V@60Hz, 110V@50Hz)

Power S/W Off Off mode - Off Off 1W

7 MTBF 50,000 HRS with 90% Confidence level Lamp Life

50,000 Hours(min)

8 Using Altitude 5,000 m (for Reliability) 3,000m(for FOS)

9 Operating Environment Temp : 10°C ~ 35°C

Humidity : 20 % ~ 80 %

10 Storage Environment Temp : -10°C~60°C non condensing

Humidity : 5 % ~ 90 % non condensing

- 8 -

LGE Internal Use Only

6. Optical characteristic specification

6.1 Optical characteristic (Module)

* Optical Test Condition

- Surrounding Brightness Level : dark

- Surrounding Temperature : 25 ± 5°C

- warm-up Time : 30 Min

- Input Siganl : RGB-PC/AV/Component/TV

- Contrast, Brightness : Outgoing condition

6.2 Chroma

No Item Min Typ Max Remark

1. Cool Wx 0.255 0.285 0.315 In AV/Component

Wy 0.263 0.293 0.323 /TV input White 85IRE

2. Normal Wx 0.265 0.295 0.325

Wy 0.275 0.305 0.335

3. Warm Wx 0.283 0.313 0.343

Wy 0.299 0.329 0.359

4. 6500k Wx 0.283 0.313 0.343 In RGB-PC input Full White 100IRE

Wy 0.299 0.329 0.359

5. 9300k Wx 0.253 0.283 0.313

Wy 0.268 0.298 0.328

No. Item Specification Min. Typ. Max. Remark

1. Viewing Angle<CR≥10> Right/Left 70/70 85/85

Up/Down 60/70 75/85

2. Luminance Luminance RGB-PC 250 300

APC : Clear, ACC : 6500K

(cd/m2) Full White (100 IRE)

AV/TV component 200 250

APC : Clear, ACC : Cool

Full White (100 IRE)

White Luminance Uniformity 75

3. Contrast Ratio CR RGB-PC/AV 700 1000 At DFC Mode

TV/ Component Min 20.000 : 1

4. CIE Color Coordinates White Wx 0.313

Wy 0.329

In RGB-PC input

RED Rx Typ 0.641 Typ

-0.03

0.335 +0.03 APC: Clear

Green Gx 0.298 ACC: 6500K

Gy 0.611 White

Blue Bx 0.147 (100 IRE)

By 0.070

LGE Internal Use Only

- 9 -

7. Model Specification

No Item Specification Remark

1. Market BRAZIL / PERU

2. roadcast ing system

PAL N/M, NTSC M

BRAZIL

RF Input Channel

VHF : 2 ~13 UHF : 14~69 CATV : 1~125

NTSC

4. CVBS Input (1EA) PAL N/M, NTSC

3 System(Rear) : PA L 50/60, NTSC

5. S-Video Input (1EA ) PAL N/M, NTSC

3 System(Rear) : PAL 50/60, NTSC

6. Component Input (1EA) Y/ Pb/Pr 480i/480p/576i/576p/720p/1080i

RGB-PC

Max1680 * 1050 @60 Hz

7. GB Input (1EA) RGB-DTV

480p, 576p, 720p, 1080i

8. I Input (1EA) DV I-PC

I Input (1EA) HM DI-DTV

480p, 576p, 720p, 1080i

10. Audio Input (3 EA) CVBS, PC Audio, Component

L/R Input

HDM

Max1680 * 1050 @60 Hz

DVI-DTV 480p, 576p, 720p, 1080i

* The spec range of Color coordinates is same with the one of module, because this model does not adjust white balance.

* Active area

- Active area of LCD PANEL is in bezel of cabinet.

- Interval between active area and bezel | A-B|<1.0 mm , | C-D|<1.0 mm

A: Interval between left of active area and bezel B: Interval between right of active area and bezel C: Interval between top of active area and bezel D: Interval between bottom of active area and bezel

Active Area

Bezel

- 10 -

LGE Internal Use Only

8. General Specification

No Item Specification Remark

ENERGE

SYNC (V /H) VIDEO LED COLOR

POWER

CONSUMPTION

55W Max.

On mode

On/On

Active Blue

50W

Typ.

Off/On

Power S/W

Sleep mode

On/Off

Off Amber

Power S/W

Off

Off mode

Off Off

D-SUB

Pin confi gurati on

1 : RED 3 : Blue 5 : S.T (GND) 7 : Green GND 9 : N.C 11: ID0 (GND) 13: H-Sync 15: SCL

2 : Green 4 : ID2 (GND) 6 : RED GND 8 : Blue GND 10: D-GND 12:SDA 14: V-Sync Shell: GND

10: Digital GND

3. MTBF

50,000 HRS with 90% Confidence level

Lamp Lif e : 50,000 Hours(min)

4. Using Altitu de 5,000 m (for Reliabilit y) 3,000m(for FOS)

Control Function

1) Contrast/Brightness/Co lor/Sharpness/Tint

2) Power On/Off, Input select, Menu, Enter, Volume ( , ), ( , )

No.

Specification

Remark

Resolution H-freq(kHz) V-freq(Hz) Pixel clock(MHz)

1. 720*480 15.73 59.94 13.500 480i

2. 720*480 15.75 60.00 13.514 480i

3. 720*576 15.625 50.00 13.500 576i

4. 720*480 31.47 59.94 27.000 480p

5. 720*480 31.50 60.00 27.027 480p

6. 720*576 31.25 50.00 27.000 576p

7. 1280*720 44.96 59.94 74.176 720p

8. 1280*720 45.00 60.00 74.250 720p

9. 1280*720 37.50 50.00 74.25 720p

10. 1920*1080 33.72 59.94 74.176 1080i

11. 1920*1080 33.75 60.00 74.250 1080i

12 1920*1080 28.125 50.00 74.250 1080i

9. Component Video Input (Y, PB, P

LGE Internal Use Only

- 11 -

No. Resolution H-freq(kHz) V-freq(Hz) Pixel clock(MHz) Remark

1. 720*480 31.47 59.94 27.000 480p

2. 720*480 31.50 60.00 27.027 480p

3. 720*576 31.25 50.00 27.000 576p

4. 1280*720 37.5 50.00 74.250 720p

5. 1280*720 44.96 59.94 74.176 720p

6. 1280*720 45.00 60.00 74.250 720p

7. 1920*1080 33.72 59.94 74.176 1080i

8 1920*1080 33.75 60.00 74.250 1080i

9 1920*1080 28.125 50.00 74.250 1080i

No. Resolution H-freq(kHz) V-freq(Hz) Pixel clock(MHz) Remark

1 720*400 31.468 70.08 28.321

2 640*480 31.469 59.94 25.175

3 640*480 37.5 75 31.5

4 800*600 37.879 60.317 40.0

5 800*600 46.875 75.0 49.5

6 1024*768 48.363 60.0 65.0

7 1024*768 60.123 75.029 78.75

8 1152*864 67.500 75.000 108.0

9 1280*1024 63.981 60.02 108.0

10 1280*1024 79.976 75.035 135.0

11 1680*1050 64.674 59.883 119.0

12 1680*1050 65.290 59.954 146.25

*

* *

**

***

****

10. RGB

10.1 Input ( PC )

10.2 Input ( DTV)

10.13 EDID Data

+ 24 hidden pages