HP L1940T User manual

HP L1940T
1
19” LCD Monitor
L1940T Series
THESE DOCUMENTS ARE FOR REPAIR SERVICE INFORMATION ONLY. EVERY REASONABLE
EFFORT HAS BEEN MADE TO ENSURE THE ACCURACY OF THIS MANUAL; WE CANNOT GUARANTEE THE
ACCURACY OF THIS INFORMATION AFTER THE DATE OF PUBLICATION AND DISCLAIMS RELIABILITY FOR
CHANGES, ERRORS OR OMISSIONS.
SERVICE MANUAL

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Table of Contents
Table of Contents ------------------------------------------------------------------------------------------------------------------------ 02
Revision List ------------------------------------------------------------------------------------------------------------------------------ 03
1.Monitor Specification ----------------------------------------------------------------------------------------------------------------04
2.LCD Monitor Description ------------------------------------------------------------------------------------------------------------05
3.Operation Instructions ---------------------------------------------------------------------------------------------------------------05
3.1 General Instructions ---------------------------------------------------------------------------------------------------------------05
3.2 Control Button ---------------------------------------------------------------------------------------------------------------------06
3.3 Adjusting The Picture --------------------------------------------------------------------------------------------------------------06
4. Input/Output Specification -------------------------------------------------------------------------------------------------------- 09
4.1 Input Signal Connector -----------------------------------------------------------------------------------------------------------09
4.2 Factory Preset Display Modes --------------------------------------------------------------------------------------------------11
4.3 Power Supply Requirements ----------------------------------------------------------------------------------------------------11
5.Panel Specification ---------------------------------------------------------------------------------------------------------------------12
5.1 General Feature --------------------------------------------------------------------------------------------------------------------12
5.2 Optical Characteristics ------------------------------------------------------------------------------------------------------------13
6.Monitor Exploded View -----------------------------------------------------------------------------------------------------------------14
7.Repair Flow Chart ---------------------------------------------------------------------------------------------------------------------15
8. Trouble Shooting -------------------------------------------------------------------------------------------------------------------18
9. Block Diagram --------------------------------------------------------------------------------------------------------------------19
10. Schematic ------------------------------------------------------------------------------------------------------------------------------20
10.1Main Board ----------------------------------------------------------------------------------------------------------------------20
10.2 Inverter/Power Board -------------------------------------------------------------------------------------------------------25
10.3 Key Board ------------------------------------------------------------------------------------------------------------------29
11. PCB Layout -----------------------------------------------------------------------------------------------------------------------------31
11.1 Main Board --------------------------------------------------------------------------------------------------------------------------31
11.2 Inverter/Power Board -------------------------------------------------------------------------------------------------------------32
11.3 Key Board ---------------------------------------------------------------------------------------------------------------------------33
12. Maintainability -------------------------------------------------------------------------------------------------------------------------34
13. White-Balance, Luminance Adjustment ------------------------------------------------------------------------------------ 35
14. Check List after replacing LCD Main board ---------------------------------------------------------------------------------37
14.1 Check white-balance -------------------------------------------------------------------------------------------------------------37
14.2 Steps for writing DDC ------------------------------------------------------------------------------------------------------------37
15. EDID Content --------------------------------------------------------------------------------------------------------------------------52
16. BOM List --------------------------------------------------------------------------------------------------------------------------53～64

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Revision List
Revision Date Revision History TPV Model
A00 Feb.-24-06 Initial release T981KMVDBHHPNP

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1.Monitor Specifications
LCD Panel
Driving system TFT Color LCD
Panel M190E5-L0A
Active Area 376.32(H) x 301.056(V) (19.0")
Pixel pitch 0.294( H )x 0.294mm( V )
ViewingAngles(Min / TYP) H:120/140; V:110/130
Response time (typ.) < 8 ms
Brightness 200 nits
Contrast 450:1
Video Analog /Digital
Input
Sync. Type H/V TTL
H-Frequency 30kHz – 83kHz
V-Frequency 56Hz – 76Hz
Display Colors Over 16 million Colors
Pixel Clock 140MHz
Max. Resolution 1280 x 1024
Plug & Play VESA DDC2BTM
Power Consumption
ON Mode ≤70W
OFF Mode <1W
Sleep Mode <2W
Power Source 100~240VAC,47~63Hz
Environmental
Considerations
Operating Temp: 5°C to 35°C
Storage Temp.: -20°C to 60°C
Operating Humidity: 20% to 80%
Main Dimensions Unpackaged(W*H*D) 413mm*477mm*265mm
Packaged(W*H*D) 524mm*513mm*239mm
Weight (N. W.) Packaged 10.22Kg Unit max
Unpackaged 8.4Kg Unit max
Altitude Operating 0 to 12,000 feet
Non-Operating 0 to 40,000 feet

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2. LCD Monitor Description
The LCD Monitor will contain main board, power board, key board and which house the flat panel control logic,
brightness control logic and DDC.
The power board will provideAC to DC Inverter voltage to drive the backlight of panel and the main board chips
each voltage.
3. Operation Instructions
3.1 General Instructions
Press the power button to turn the monitor on or off. The other control buttons are located at front of the panel.
By changing these settings, the picture can be adjusted to your personal performance.
-The power cord should be connected .
-Connect the video cable from the monitor to the computer VGAcard.
-Press the power button to turn on the monitor, the power indicator will light up to Green.
Video signal, DDC
Power Board
Flat Panel and
CCFL backlight
Main Board
Keyboard
RS232 Connector
For white balance
adjustment in
factory mode
HOST Computer
CCFT Drive.
AC-IN
110-240V
Monitor Block Diagram

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3.2 Control Buttons
-Power Indicator:
Green — Power On mode.
Orange — Power Saving mode.
Blank —Power Off Mode.
Auto Adjust : Activates the auto adjustment feature for optimum image.
Menu : Opens the ON-Screen Display(OSD) menu.
Minus (–) :1、If OSD is on, press to navigate backward through the OSD menu features and decrease
adjustment levels.
2、If OSD is off, press to enable the DVI signal input (available on select models).
plus (+) :1、If OSD is on, press to navigate forward through the OSD menu features and increase adjustment
levels.
2、If OSD is off, press to enable the VGA signal input.
Power: Turns the monitor on or off.
3.3 Adjust the Picture
Main Menu
Press the “Menu” button, the Main Menu should be come on the screen of the monitor

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Service Mode
Press and hold the “Menu” button, Power off -> on “Power”,then into the service mode, Press “menu” button to
bring to OSD menu for confirmation as below:
Factory Mode
1、Turn off monitor.
2、[ Push “Auto Adjust” and “+ (plus)”and hold them at the same time ]+ [ Press power “Power” button untill
comes out “windows screen” ] =>then release all button,then press “Menu”button,wait untill the OSD
menu with Characters “F” (below OSD menu) come on the Screen of the monitor as bellow:
3、Pust “Menu” to exit OSD menu.
Factory Mode Indicator

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Menu icons
No. Control Icon
1 Brightness
2 Contrast
3 Auto Adjustment
4 Image Control
5 Color
6 Custom Color
7 Language
8 Management
9 OSD Control
10 Information
11 Factory Reset
12 Default Video Input
13 Horizontal Position
14 Vertical Position
15 Clock
16 Clock Phase
17 Power Saver
18 Mode Display
19 Power-On Status Display
20 Sleep Timer
21 Basic Menu
22 Advanced Menu
23 Power On Recall
24 Horizontal OSD Position
25 Vertical OSD Position
26 OSD Timeout
27 OSD Transparency
28 Exit

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4. Input/Output Specification
4.1 Input Signal Connector
Analog Connector Pinout
Pin Mnemonic Signal Pin Mnemonic Signal
1 RV Red Video 9 +5 V +5 V (from PC)
2 GV Green Video 10 SG Sync Ground
3 BV Blue Video 11 NC None
4 NC None 12 SDA DDC Data
5 GND GND / Cable Detect 13 HS Horizontal Sync
6 RG Red GND 14 VS Vertical Sync
7 GG Green GND 15 SCL DDC Clock
8 BG Blue GND
VGA connector layout
PIN 1 PIN 5
PIN 11

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DVI-D Digital Connector Pins
Pin. Mnemonic Signal Pin. Mnemonic Signal
1 TX 2 - TMDS Negative differential input, channel 2 13 TX 3 + TMDS Data 3 +
2 TX 2 + TMDS Positive differential input, channel 2 14 +5V +5V Power
3 SHLD 2 / 4 Shield for TMDS channels 2 / 4 15 GND GND / Cable Detect
4 TX 4 - TMDS Data 4 - 16 HPD Hot Plug Detect
5 TX 4 + TMDS Data 4 + 17 TX 0 - TMDS Data 0 -
6 DDC Clk DDC Clock 18 TX 0 + TMDS Data 0 +
7 DDC Data DDC Data 19 SHLD 0 / 5 TMDS Data 0 / 5 Shield
8 AVS Analog Vertical Sync 20 TX 5 - TMDS Data 5 -
9 TX 1 - TMDS Data 1 - 21 TX 5 + TMDS Data 5 +
10 TX 1 + TMDS Data 1 + 22 TX CLK SHLD TMDS Clock Shield
11 SHLD 1 / 3 TMDS Data 1 / 3 Shield 23 TX CLK + TMDS Clock +
12 TX 3 - TMDS Data 3 - 24 TX CLK - TMDS Clock -
DVI-D Digital Connector Pins