Daewoo Lucoms CML-523BM User manual

LCD COLOR MONITOR
Model : CML-523BM
http://www.lucoms.com MAY. 2004
Service Manual
DAEWOO LUCOMS CO., LTD.

SAFETY PRECAUTIONS 2
GENERAL SAFETY INFORMATION 3
SERVICING PRECAUTIONS 4
TECHNICAL INFORMATION 8
GENERAL INFORMATION 8
PIN CONNECTOR 9
CAUTIONS FOR ADJUSTMENT AND REPAIR 9
OPERATION & ADJUSTMENT 10
ALIGNMENT PROCEDURE 16
TROUBLESHOOTING HINTS 17
BLOCK DIAGRAM 25
SCHEMATIC DIAGRAM 26
PCB PATTERN 34
INFORMATION OF PART DESCRIPTION 38
ELECTRICAL PARTS LIST 39
CONTENTS
1

2
SAFETY PRECAUTIONS
◆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.
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.

3
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.

4
SERVICING PRECAUTIONS
◆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.
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).
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.
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.
CAUTION: A wrong part substitution or incorrect polarity installation of electrolytic capacitors
may result in a explosion.
CAUTION: This is a flammable mixture. Unless specified in this service manual, lubrication of
contacts is not required.

5
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 “anti-
static” 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.
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: Be sure that no power is applied to the chassis or circuit, and observe all other safety
precautions.
CAUTION: Work quickly to avoid overheating the circuit board printed foil.

6
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.

7
◆ 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.
SERVICING PRECAUTIONS

8
TECHNICAL INFORMATION
Panel Size 15-inch (38cm) diagonal
Pixel Pitch 0.297 x 0.297mm
Viewing Angle 70°(Right/Left)
70°(up), 60°(down)
Contrast Ratio 350:1 contrast ratio (typ)
Brightness 250cd/m2brightness (typ)
Color Filter RGB vertical stripe
Synchronization Horizontal 30-62KHz
Vertical 50-75Hz
Video Bandwidth 80MHz
Max Resolution 1024 x 768 @75Hz
Colors 16.2M Colors
Display Area 304.1mm x228.1mm
PC Input Signal Sync H/V separate (TTL)
Video 15 pin mini D-sub(Analog RGB)
Audio Stereo MiniJack Input & Output
Speaker Max. Output 2W(Left 1W+Right 1W)
Plug and Play VESA DDC Compatible
Power Source 100-240Vac, 50/60Hz (Free Voltage)
Power Consumption 26W
Dimension-W x H x D 370 x 352 x 205mm (with stand)
370 x 312 x 60mm (without stand)
Weight-net/gross 4.2/5.5Kg
Power Saving EPA, VESA DPMS, Nutek Compliant
Tilt Range 5° forward, 30° backward
Operating Temperature 10 ~ 40°C /50 ~ 104°F

9
Arrangement of 15-pin D-sub connector
Pin Signal
1 Red
2 Green
3 Blue
4 GND
5 GND
6 GND - Red
7 GND - Green
8 GND - Blue
9 +5Vdc
10 GND - H.Sync
11 GND - V.Sync
12 Bi-directional Data (SDA)
13 Horizontal Sync
14 Vertical Sync (VCLK)
15 Data Clock (SCL)
1
610
15
PIN CONNECTOR
• 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.
CAUTIONS FOR ADJUSTMENT AND REPAIR
This TFT LCD monitor automatically scans all horizontal frequencies from 30KHz to 62KHz. 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 1024 dots and a maximum
vertical resolution of 768 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
GENERAL INFORMATION

10
OPERATION AND ADJUSTMENT
Control Panel
<< L523BM >>
*
( ) : Hot Key
Switches the monitor on and
off. Shows both normal operation and
power management status with
power indicator light.
POWER Indicator
POWER
1
34
2
Moves cursor to the right or low
window in the OSD window and
increases the value of any
selected function.
Moves cursor to the left or high
window in the OSD window and
decreases value of any selected
function.
( )
EXIT/POWER LIGHT
MENU 6
5
Turns the OSD (On-Screen
Display) window off and moves
from sub menu to top menu in the
OSD window.
While the OSD screen is off, you
can adjust the screen brightness
according to each situation.
Turns the OSD window on.
AUTO
7
Launches the AUTO TRACKING
function directly.
*
( )
AUTO EXIT
POWER LIGHT
MENU BRIGHTNESS
1
76453
2
*( )
*

11
OPERATION AND ADJUSTMENT
Key Process
OSD OFF
OSD
OSD
1024X768 60K 75
UTILITY
UTILITY UTILITY
SHARPNESS SHARPNESS
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
AUTO TRACKING
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.
POWER LIGHT
PC MODE
GAME MODE
MOVIE MODE
AUTO
BRIGHTNESS
POWER LIGHT
EXIT
HOT KEY

12
Adjustment Procedure
OPERATION AND ADJUSTMENT
Adjust the CLOCK
control.
Perform the AUTO
POSITION.
Is the H.Size
proper?
Is the
noise displayed on
the screen?
Perform the AUTO
TRACKING.
Is the
noise displayed on
the screen yet?
Is the
noise displayed on
the screen yet?
Adjust the CLOCK FINE
until the screen is
cleared.
Yes
Yes
Yes
Yes
No
No
No
No End

13
OPERATION AND ADJUSTMENT
Adjust the blue color.
Adjust the red color.
AUTO TRACKING Adjust the horizontal & vertical picture image quality and size.
Adjust the width (horizontal size) of the screen image.
CLOCK
R
G
Sharpen the focus by aligning the illuminated pixels and adjust until the screen
image looks focused, crisp and sharp. Adjusting the CLOCK FINE after the
CLOCK adjustment will produce a clear screen.
Adjust the green color.
CLOCK FINE
RED CONTROL
GREEN
CONTROL
OSD Functions
Adjust the display image quality (if the screen proceed to scaling up).
SHARPNESS
B
Adjust the OSD position horizontally (left or right) and vertically (up or down).
OSD POSITION
OSD
Choose different preset color temperatures or set your own customized color
parameters.
COLOR
TEMPERATURE
Adjust the position of the display horizontally (left or right) and vertically (up or
down).
BLUE CONTROL
H. CENTER &
V. CENTER
Reset the screen to the Factory Preset Display Settings.
RECALL
Display horizontal & vertical frequency and polarity.
STATUS
OSD TIME OUT Adjust the display OSD Menu.
<< OSD FUNCTIONS WITH USING PC >>
Adjust audio volume, mute sound.
VOLUME
ICON CONTROL FUNCTIONS

14
OPERATION AND ADJUSTMENT
Select language for OSD (6 languages).
LANGUAGE
Choose automatically the proper horizontal position and vertical position & size
of the screen image.
AUTO POSITION
Adjust the contrast of image, the difference between light and dark areas on the
screen.
CONTRAST
ICON CONTROL FUNCTIONS

15
Self Diagnosis
If there is no image, the Self Diagnosis screen will be displayed. Self Diagnosis function checks if the
status of the monitor screen is No Signal, Out of range or None support.
“No Signal” screen is displayed when the D-Sub signal connector is not
connected or the status of the monitor is on DPMS mode.
“Out of Range” screen is displayed when the applied frequency is under or over
normal range.
Normal range
(Non-interlaced mode only)
OPERATION AND ADJUSTMENT
“None support” screen is displayed when the applied frequency is under or over
factory preset timings.
Check cable screen is displayed when the
signal cable is disconnected.
H : 30 - 62 KHz
V : 50 - 75 Hz

16
Standard Check point
1. Power source : 100 - 240Vac, 50/60Hz.
2. Aging : Take at least 20 minutes warm-up time.
3. Signal
• Video input : Analog 0.7Vpp 75Ωterminal positive polarity
• Synchronizing : acceptable negative or positive at TTL level
• Max. Resolution :
15”-1024 x 768@75Hz
• Frequency:
15”-Horizontal : 30KHz - 62KHz
Vertical : 50Hz - 75Hz (available only non interlace mode)
Adjustment
1. Sharpness set to 0%
2. Contrast set to 100%
3. Brightness set to 100%
4. Switching to factory alignment mode
Press power key with Brightness left key at the power off status.
5. Set up the tracking
See the SVC manual at page 14th.
6. Switching to user’s mode
If turn-off and turn-on then switched to user’s mode.
*All of adjusted data stores by fade out of OSD.
ALIGNMENT PROCEDURE

17
TROUBLESHOOTING HINTS
Is a input
H-sync of Scaler(pin 126,
U6) correct?
Abnormal mode
detect
No
Yes
Trouble in the H-sync
input circuit.
Trouble
in Scaler(U6).
Yes
1. Abnormal mode detect
1-1. Abnormal mode detect for PC Source

18
TROUBLESHOOTING HINTS
No
No
Yes
Yes
Is Vcc 5V line
normal(pin 8 of CON1)?
Trouble in Scaler(U6).
Check the power board
(Vcc 5V of CN2A).
Check on Scaler(U6).
Is the
Power LED toggled
between on and
off?
Off
No
Yes
On
Is the power
cord well
connected?
Refer to No video
or No raster.
Check if the power switch
is on position and
Connect the power
cord correctly.
Check the
waveform of pin 17
of -com(U4).
Trouble in
Power on
Yes
2. Trouble in Power on

19
TROUBLESHOOTING HINTS
3. No Raster
Is 12V
plugged in pin5
of CN2(power
board)?
No
No
Yes
Yes
Is the output of
inverter correct?
Check the output
of D811 12V line
(power board).
Replace the inverter.
Replace a LCD panal.
Check the
output of Q1 or
pin 15 of U4. Trouble in pin 15
of -com.
No Raster
Yes
low
high