DAEWOO CML-710 Service Manual

Service Manual

LCD COLOR MONITOR

Model : CML-710

DAEWOO LUCOMS CO., LTD.

http://www.lucoms.com 2004

CONTENTS

SAFETY PRECAUTIONS	2
GENERAL SAFETY INFORMATION	3
SERVICING PRECAUTIONS	4
TECHNICAL INFORMATION	8
GENERAL INFORMATION	9
PIN CONNECTOR	9
CAUTIONS FOR ADJUSTMENT AND REPAIR	9
OPERATION & ADJUSTMENT	10
ALIGNMENT PROCEDURE	16
TROUBLESHOOTING HINTS	17
BLOCK DIAGRAM	24
SCHEMATIC DIAGRAM	25
PCB PATTERN	30
INFORMATION OF PART DESCRIPTION	34
ELECTRICAL PARTS LIST	35

1

SAFETY PRECAUTIONS

CAUTION: No modifications of any circuits 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 the inverter that generates the high voltage to lighten CCFL of the LCD panel.

Fire & Shock Hazard

•Insert an isolation transformer between the analog color display and AC power line before servicing the chassis.

•When servicing, pay close attention to the original lead dress especially in the high voltage circuit area; 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 original design.

•Soldering must be inspected for possible cold solder points, frayed leads, damaged insulation, solder splashes or sharp solder points. Be certain to remove all foreign materials.

2

GENERAL SAFETY INFORMATION

Terms in the manual

CAUTION	Statements identify conditions or practices that could result in damage to the equipment or
	other property.
WARNING	Statements identify conditions or practices that could result in personal injury or loss of
	life.
Terms as marked on equipment
CAUTION	Statements indicate a personal injury hazard not immediately accessible as one reads the
	marking or a hazard which is properly included on the equipment itself.
WARNING	Statements are clearly concerning indicated personal injury hazards.

Symbols in the manual

The symbols indicate where applicable cautionary or other information is to be found.

Symbols as marked on equipment

Protective GROUND terminal

High Voltage Warning And Critical Component Warning Label

The following warning label is on the inverter isolation case.

3

SERVICING PRECAUTIONS

CAUTION: Before servicing instruments covered by this service manual, its supplements, and addendum, please read and follow the SAFETY PRECAUTIONS of this manual.

NOTE: If unforeseen circumstances create conflict between the following servicing precautions and any of the safety precautions on page 1 of this manual, always follow the safety precautions. Remember: Safety First.

General Servicing Precautions

1.Always unplug the AC power cord from the AC power source before:

a. Removing or reinstalling any component, circuit board, module, or any other instrument assembly.

b.Disconnecting or reconnecting any electrical plug or other electrical connection.

c.Connecting a test substitute in parallel with an electrolytic capacitor in the instrument.

CAUTION: A wrong part substitution or incorrect polarity installation of electrolytic capacitors may result in a explosion.

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 any spray chemicals on or near this instrument, or any of its assemblies.

4.Unless otherwise specified in this service manual, only clean electrical contacts by applying the following mixture to the contacts with a pipe cleaner, cotton-tipped stick, or comparable nonabrasive applicator: 10% (by volume) Aceton and 90% (by volume) isopropyl alchohol (90%-99% strength).

CAUTION: This is a flammable mixture. Unless specified in this service manual, lubrication of contacts is not required.

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

6.Always connect the test instrument ground lead to the appropriate instrument chassis ground before connecting the test instrument positive lead. Always remove the test instrument ground lead last.

7.Only use the test fixtures specified in this service manual with this instrument.

4

SERVICING PRECAUTIONS

Electrostatically Sensitive (ES) Devices

Some semiconductor (solid state) devices can be damaged easily by static electricity. Such components are commonly called Electrostatically Sensitive (ES) Devices.

The typical examples of ES devices are integrated circuits, 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 electricity.

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

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

3.Only use a grounded-tip soldering iron to solder or unsolder ES devices.

4.Only use an anti-static type solder removal device. Some solder removal devices not classified as “antistatic” can generate enough electrical charges to damage ES devices.

5.Do not use freon-propelled chemicals. These can generate enough electrical charges 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 replacement ES devices, touch the protective material to the chassis or circuit assembly into which the device will be installed.

CAUTION: Be sure that no power is applied to the chassis or circuit, and observe all other safety precautions.

8.Minimize bodily movements when handling unpackaged replacement ES devices. (Otherwise harmful motion such as the brushing together clothes fabric or the lifting your foot from a carpeted floor can generate enough static electricity to damage ES devices).

General Soldering Guidelines

1.Use a grounded-tip, low-wattage soldering iron with appropriate tip size and shape that will maintain tip temperature between a 550°F-660°F (288°C-316°C) range.

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.

4.Throughly clean the surface to be soldered. Use a small wire-bristle (0.5 inch or 1.25cm) brush with a metal handle. Do not use freon-propelled spray-on cleaners.

5.Use the following soldering technique:

a.Allow the soldering iron tip to reach normal temperature (550°F to 660°F or 288°C to 316°C)

b.Hold the soldering iron tip and solder 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 until the solder flows onto and around both the component lead and the foil.

d.Closely inspect the solder area and remove any excess or splashed solder with a small wire-bristle brush.

CAUTION: Work quickly to avoid overheating the circuit board printed foil.

5

SERVICING PRECAUTIONS

FIGURE 1. USE SOLDERING IRON TO PRY LEADS

IC Removal/Replacement

Some utilized chassis circuit boards have slotted (oblong) holes through which the IC leads are inserted and then bent flat against the circuit foil. When holes are slotted, 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 on the page under the title of general soldering guidelines.

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 desoldering 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. (lt is not necessary to reapply acrylic coating to the area).

“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 the ends of each of three leads remaining on the circuit board into a “U” shape.

3.Bend the replacement transistor leads into a “U” shape.

4.Connect the replacement transistor leads to the corresponding leads extending from the circuit board and crimp the “U” with long nose pliers to ensure metal-to-metal contact, then solder each connection.

Power IC, Transistor or Devices Removal/Replacement

1.Heat and remove all solders from the device leads.

2.Remove the heatsink mounting screw (if applicable).

3.Carefully remove the device from the circuit board.

4.Insert new device in circuit board.

5.Solder each device lead and then clip off excess lead.

6.Replace heatsink.

6

SERVICING PRECAUTIONS

Diode Removal/Replacement

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

2.Bend the two remaining leads perpendicularly to the circuit board.

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

4.Securely crimp each connection and solder it.

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

7

TECHNICAL INFORMATION

Panel	Size	17-inch (43.2 cm) diagonal
	Pixel Pitch	0.264 x 0.264 mm
	Viewing Angle	70°(Right/Left)
		60°(up), 60°(down)
	Contrast Ratio	400:1 contrast ratio (typ)
	Brightness	250cd/m2 brightness (typ)
	Color Filter	RGB vertical stripe
Synchronization	Horizontal	30 - 80 KHz
	Vertical	56 - 77 Hz
Video Bandwidth		135 MHz
Max Resolution		1280 x 1024@75Hz
Optimal Resolution		1280 x 1024@75Hz
Colors		8 bit (16M Colors)
Display Area		337.9mm x 270.3mm
PC Input Signal	Sync	H/V separate (TTL)
	Video	15 pin mini D-sub(Analog RGB)
Plug and Play		VESA DDC Compatible
Power Source		100-240 Vac, 50/60 Hz (Free Voltage)
Power Consumption		40 W
Dimension-W x H x D		386 x 398 x 190 mm (with stand)
(without speaker)		386 x 346 x 60 mm (without stand)
Weight-net/gross		6.2/7.6 Kg(13.6/16.7 lbs)
Power Saving		EPA, VESA DPMS, Nutek Compliant
Tilt Range		5° forward, 30° backward
Operating Temperature		10 ~ 40°C /50 ~ 104°F

8

GENERAL INFORMATION

This TFT LCD monitor automatically scans all horizontal frequencies from 30KHz to 80KHz, and all vertical frequencies from 56Hz to 77Hz(15”- 50KHz to 75KHz). This TFT LCD monitor supports IBM PC, PC/XT, PC/AT, personal System/2 (PS/2), Apple Macintosh, and compatible users crisp text and vivid color graphics display when using the following graphics adapters : (VGA, Super VGA, VESA, XGA, SXGA and Apple Macintosh Video Card). And so, this TFT LCD monitor has a maximum horizontal resolution of 1280 dots and a maximum vertical resolution of 1024 lines for superior clarity of display.

By accepting analog signal inputs which level is zero to 0.7 Volts. This TFT LCD monitor can display 16.7M colors depending on the graphics adapter and software being used.

Abbreviations

ADJ			Adjustment
AFC			Automatic Frequency Control
TFT-LCD			Thin Film Transistor Liquid Crystal Diplay
CCFL			Cold Cathode Fluorescent Lamp
H.SYNC			Horizontal Synchronization
OSC			Oscillator
P.S.U			Power Supply Unit
PWA			Printed Circuit Board Wiring Assembly
R.G.B			Red, Green, Blue
V.Sync			Vertical Synchronization
ADC			Analog Digital Converter
PIN CONNECTOR
Pin	Signal			1
1	Red
2	Green
3	Blue			6	10
4	GND
5	GND
6	GND - Red				15
7	GND - Green
8	GND - Blue
9	+5Vdc			Arrangement of 15-pin D-sub connector
10	GND - H.Sync
11	GND - V.Sync
12	Bi-directional Data (SDA)
13	Horizontal Sync
14	Vertical Sync (VCLK)
15	Data Clock (SCL)

CAUTIONS FOR ADJUSTMENT AND REPAIR

•The white balance adjustment has been done by a color analyzer in factroy. The adjustment procedure, described in the service manual is made by a visual check.

•Allow 20 minutes warm-up time for the display before checking or adjusting only electrical specification or function.

•Reform the leadwire after any repair work.

Caution For Servicing

•In case of servicing or replacing inverter, high voltage sometimes remains in the output of the inverter. Completely discharge high voltage before servicing or replacing inverter to prevent a shock to the serviceman.

9

OPERATION AND ADJUSTMENT

<< L710 >>

1 POWER

Swithes the monitor on and off.

2 POWER Indicator

Shows both normal operation and power management status with power indicator light.

8 7 6 1

3 (*)

Moves cursor to the right or low window in the OSD window and increases the value of any selected function.

5 POWER LIGHT

While the OSD screen is off, you can adjust the screen brightness according to each situation.

5 4 3

2

4 (*)

Moves cursor to the left or high window in the OSD window and decreases value of any selected function.

6 SELECT

Moves from top menu to sub menu in the OSD window and opens the function window for the selected icon.

7 MENU/EXIT

Turns the OSD window on.

Turns the OSD (On-Screen Display) window off and moves from sub menu to top menu in the OSD window.

8 AUTO (*)

Launches the AUTO TRACKING function directly.

(*) : Hot Key

10

OPERATION AND ADJUSTMENT

Key Process

MENU
1280X1024 80K 75	UT L TY	UT L TY
	OSD	OSD
	SELECT	SELECT

EXIT

EXIT

UT L TY

SHARPNESS

SHARPNESS

EXIT

11

OPERATION AND ADJUSTMENT

HOT KEY

AUTO

AUTO TRACKING

BRIGHTNESS /

POWER LIGHT

POWER LIGHT

PC MODE

GAME MODE

MOVIE MODE

When there is no OSD, if you press this AUTO button, you can use the best display performance fit for a current mode.

When there is no OSD, if you press this BRIGHTNESS button, you can adjust the brightness directly.

: decreases brightness

: increases brightness

The screen will be brightened progressively by 10%. If you carry out general PC works such as document edition on the Movie mode,you may shorten the life span of LCD panel. Thus,it is recommended to verify the selected mode before use.

12