Tatung L7CMS User manual

L7CMS/L7CMT
Tatung LCD Monitors
Service Manual
Ver 1.0

L7C SERIES LCD Monitor Service Manual (v1.0)
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TABLE OF CONTENTS
1. Precaution and Notices … … … … .……………………………………… 3
1.1Safety Precaution … … … … .……………………………………….3
1.2 Product Safety Notice ……………………………………………… 3
1.3 Service Notes ……………………………………………………….3
2. Specifications … … … … .……………………………... … … … … … … … 4
2.1Monitor Specifications … ….. ……………………………………….4
2.2Timing Supported –Analog Inputs .. … … … … … … … … … … … … .5
3. Control Buttons and Functions ………………………………………….6
4. Disassembly Instructions ……………………………………………….. 6
5. General Connection and Applications ………………………………….. 6
5.1Connecting the Monitor to the Computer ………………………….. 9
6.Electronic Block Diagram …………………………………………..... 11
Appendix A. Troubleshooting Flow Chart
Appendix B. Mainboard Circuit Diagrams
Appendix C. Keyboard Circuit Diagrams
Appendix D. Audio Circuit Diagrams
Appendix E. Mechanical Disassembly
Appendix F. Service Parts List

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1. Precautions and Notices
1.1 Safety Precautions
Although LCD monitors are displays without high voltage as that in the CRTs, the
following precautions still should be take care of.
1) Observe all cautions and safety related notes located inside the display cabinet and on
the display chassis.
2) Operation of these displays outside the cabinet or with the cover removed involves a
shock hazard from the display backlight’s inverter. Work on the display should not be
attempted by anyone who is not thoroughly familiar with precautions necessary when
working on high voltage equipment.
3) Before returning a serviced display to the customer, a thorough safety test must be
performed to verify that the display is safe to operate without danger or shock.
1.2 Product Safety Notice
1) Many electrical and mechanical parts in this chassis provide special visual safety
protection. The protection afforded by them cannot necessarily be obtained by using
replacement components rated for higher voltage, wattage, etc.
2) Before replacing any of these components, read the parts list manual carefully. The use
of substitute replacement parts, which do not have the same safety characteristics, as
specified in the parts list may create shock, fire or other hazards.
1.3 Service Notes
1) When replacing parts or circuit boards, wrap the wires around terminals before
soldering.
2) Keep wires away from high temperature components.
3) Keep cable and their shielding in their original position so as to reduce interference.

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2. Specifications
2.1 Monitor Specification
LCD Module 17-in, active matrix TFT, anti-glare coating, 0.264 mm pixel pitch
Display Size 337.9 mm x 270.3 mm
Viewing Angle
Left/Right
Up/Down 80°/ 80°(Typical)
40°/80°(Typical)
Luminance
Contrast Ratio 250 cd/m2(Typical) 400 : 1 (Typical)
Display Colors 16.7 million
Power Input 100 ~ 240 VAC Full Range, 50/60 Hz (External AC adapter)
Maximum power
consumption < 45W
Signal Input
Video Signal
Sync signals RGB positive 0.7VPP, 75ohm
Separate & Composite, TTL Level
Line (horizontal)
frequency 31.5 kHz ~ 80 kHz
Raster (vertical)
frequency 56 Hz ~ 75 Hz
Pixel dot clock 135 MHz (maximum)
Recommended mode 1280 x 1024 @ 60 Hz
Pedestal tilt 20°forward, -5°backward
Dimensions
(W x H x D) 424 x 438 x 86 mm (without base)
Weight 7.0 kg
Operating Conditions
Temperature
Humidity
Altitude
5°~ 40°C at altitude 0 ~ 2000m
5°~ 30°C at altitude 2000 ~ 3000m
20% ~ 85% RH, non-condensing
3000m Max.
Storage Conditions
Temperature
Humidity
Altitude
-20°~ 60°C
5% ~ 95% RH
10000m Max.

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2.2–Analog Inputs
Mode
No. Mode Name Resolution H.Freq.(KHZ) V.Freq.(HZ) H. Polarity V. Polarity Pixel CLK (MHZ)
1VGA 60HZ
640*480 31.469 59.941 －
－25.175
2VGA 72HZ
640*480 37.804 72.81 －
－31.5
3VGA 75HZ
640*480 37.5 75.0 －
－31.5
4SVGA 56HZ
800*600 35.156 56.25 ＋
＋36.0
5SVGA 60HZ
800*600 37.879 60.317 ＋
＋40.0
6SVGA 72HZ
800*600 48.077 72.188 ＋
＋50.0
7SVGA 75HZ
800*600 46.875 75.0 ＋
＋49.5
8XGA 60HZ
1024*768 48.363 60.004 －
－65.0
9XGA 70HZ
1024*768 56.476 70.069 －
－75.0
10 XGA 75HZ
1024*768 60.023 75.029 ＋
＋78.75
11 SXGA 60HZ
1280*1024 63.981 60.020 ＋
＋108
12 SXGA 75HZ
1280*1024 79.976 75.025 ＋
＋135
13 MAC SVGA
640*480 35.0 66.667 －
－30.24
14 MAC SVGA
832*624 493725 74.550 －
－57.283
15 US TEXT
720*400 31.469 70.087 －
＋28.322
16 VGA 70HZ
640*350 31.469 70.087 ＋
－25.175
Note: The display is capable of going beyond these recommended modes.

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3. Control Buttons and Functions
There are four control buttons located at the lower part of the front panel of your display:
ðPOWER:Push to turn on or turn off the display. The power indicator (Green) will light
while the display is on.
ðSelect: Display the On-Screen Display (OSD) “Main Menu”, selects items for user
adjustment, and execute the function selected.
Note: Hold down this key for 2 seconds will clear OSD menu.
ðUp( △ ): Move upward through the choice in the OSD submenu. If an adjustment bar is
displayed, this button increases the setting value.
Note: This key is also used as‘direct key’to bring-up OSD “Audio Menu”.
ðDown( ▽ ): Move downward through the choice in the OSD submenu. If an adjustment bar
is displayed, this button decreases the setting value.
Note: This key is also used as‘direct key’. When the OSD “Main Menu” is inactive, press
this key will execute‘Auto Setup’function.
Detail contral function please reference User’s Manual
4. Disassembly Instructions
To disassembly the monitor, follow the steps as below:
1)Face Down the Monitor.
Note: Face down the monitor on a smooth plane with a soft material on that plane to
protect the panel faceplate.
2)Hinge Cover Removal
As below, remove the screw indicated by “A”from the hinge cover, and then remove the
hinge cover (indicated by “B”) for the base.

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3)Base and Back Cover Removal:
As below, after removing the hinge cover, there will be 4 screws (indicated by “C”), and
remove them. Then you can remove the whole base of the monitor.
Remove 4 screws indicated as “D”of the back cover. Then remove the back cover with
care .

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4)Metallic Cover Removal:
Remove 6screws indicated as “G” from the back metallic cover. Then remove the back
metallic cover.
5)PCB Assembly Removal:
Caution: When serving or replacing the panel, disconnect the DC power jack completely.
(a)Unplug all connected wires from the PCB.
(b)Remove 3screws indicated as “K”from the inverter board, and then remove the board
carefully.
(c)Remove 2screws indicated as “J”from the audio board, and then remove the board
carefully.
(d)Remove 7 screws indicated as “I”from the main board connected with front cover.

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5. General Connection and Applications
Procedures for installing and using this CML171SX LCD monitor are described as
below.
5.1 Connecting the monitor to the computer
1) Place the display on a flat, sturdy surface. Choose an area free from excessive heat,
moisture, and sunlight. Avoid possible sources of electromagnetic interference, such as
transformers, motors, and fluorescent lighting.
2) Locate the AC power adapter with attached power cable and then connect the power cable
to the power jack on the back of the display. Plug the three-prong power cord into a power
outlet, and plug the other end into the AC power adapter. The three-prong power cord is a
shielded type and is provided as a safety precautions to ensure proper electrical grounding.
Plug the D-SUB 15-pin analog signal cable into the Analog Input port on the back of the
display. Connect the other end of the signal cable into your computer’s VGA output port. The
assignment of the pins of the connector is as follows:
Pin Assignment of 15-pin D-SUB connector
1Red Video 9+5V for DDC circuit
2Green Video 10 Logic Ground
3Blue Video 11 Monitor Ground
4Monitor Ground 12 DDC-Serial Data
5DDC-Return 13 H-Sync.
6Red Ground 14 V-Sync.
7Green Ground 15 DDC-Serial Clock
8Blue Ground

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3) First turn the PC power switch ON. Then apply power to the display by pressing the power
button to turn the monitor on. The power indicator LED will then illuminate.
Note: Do not force the cable into the connector; line it up carefully so that you don’t
bend the pins.

6. Electronic Block Diagram
RED
GREEN
BLUE
H_SYNC
V_SYNC
SCL
SDA
3.3V
12V
5V
Audio in
ANALOG R.G.B INPUT
24WC02
(DDC2B)
gmZAN1
PLL
ADC
OSD
SCALER
160 pin PQFP Package
LVDS
MICROCONTROLLER
Regulat
or
LVDS
TFT LCD PANEL
Audio Ampilier Speaker/Earphone
INVERTER

Troubleshooting Flow Chart
No No
YES
No
No
YES
YES
YES
YES
YES
NoNo
YES
No
No image appear
LED light up Voltage
ofP006
pin 1 is
5V
Replace
PWB-0319
Voltage
of C305
is 5V Replace
PWB-0265
Is the
frequency
of R005
20 MHz
Replace
X001
Replace
MCU
I003
LED display
is amber
Is it entering
power Saving
Restart PC
signal to ensure
H.V Sync. are
not absent
End
LED
display
is
Green
Replace
MCU
I003
Replace
INVERTER
Replace
PWB-0265