HP L1940T User manual

19" LCD Color Monitor HP L1940T
1
19” LCD Monitor
L1940T
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 -----------------------------------------------------------------------------------------------------------------06
3.1 General Instructions ---------------------------------------------------------------------------------------------------------------06
3.2 Control Button ---------------------------------------------------------------------------------------------------------------------06
3.3 Adjusting The Picture ----------------------------------------------------------------------------------------------------------------07
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. Block Diagram -----------------------------------------------------------------------------------------------------------------------15
8. Maintainability -----------------------------------------------------------------------------------------------------------------------------17
9. Schematic --------------------------------------------------------------------------------------------------------------------------------24
9.1 Main Board -------------------------------------------------------------------------------------------------------------------------24
9.2 Inverter/Power Board ---------------------------------------------------------------------------------------------------------29
10. PCB Layout -----------------------------------------------------------------------------------------------------------------------------31
10.1 Main Board -------------------------------------------------------------------------------------------------------------------------31
10.2 Inverter/Power Board ------------------------------------------------------------------------------------------------------------32
10.3 Key Board --------------------------------------------------------------------------------------------------------------------------32
11. White-Balance, Luminance Adjustment ------------------------------------------------------------------------------------ 33
12. EDID Content --------------------------------------------------------------------------------------------------------------------------36
13. BOM List --------------------------------------------------------------------------------------------------------------------------------37
14. Different Parts List---------------------------------------------------------------------------------------------------------------------

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Revision List
Revision Date Revision History TPV Model
A00 Sep.-08-06 Initial release T981KMNDKHHPQP
T981KGNDBHHPQP
T96HNNDBC6HPQP
T981KMNDBHHPQP
T96HNNDKC6HPQP
T96GNNDKC6HFQP
T96GNNDMC6HFQ
T96GNNDMC6HPQP
T96HNNDBC6HFQP
A01
Nov.-15-06 Add new BOM
T96HNNDMC6HFQ

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1. Monitor Specifications
Driving system TFT Color LCD
Panel M190E5-L0A
Active Area 376.32(H) x 301.056(V) (19.0")
Pixel pitch 0.294mm(H) x 0.294mm(V)
Viewing Angles (TYP) H: 150; V: 130
Response time (typ.) 8 ms
Contrast 700:1
LCD Panel
Video Analog /Digital
Sync. Type H/V TTL
H-Frequency 30kHz – 83kHz
Input
V-Frequency 56Hz – 76Hz
Display Colors Over 16 million Colors
Pixel Clock 140MHz
Max. Resolution 1280 x 1024
Plug & Play VESA DDC2BTM
ON Mode ≤70W
OFF Mode <1W
Power Consumption
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%
Unpackaged (W*H*D) 413mm*477mm*265mm
Main Dimensions
Packaged (W*H*D) 524mm*513mm*239mm
Packaged 10.22Kg Unit max
Weight (N. W.)
Unpackaged 8.4Kg Unit max
Operating 0 to 12,000 feet
Altitude
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 provide AC to DC Inverter voltage to drive the backlight of panel and the main board chips each
voltage.
Video signal, DDC
Power Board
(
Include ada
p
ter and inverter
)
Flat Panel and
CCFL backlight
Main Board
Audio board
RS232 Connector
For white balance
adjustment in
factory mode
HOST Computer
CCFT Drive.
AC-IN
110V-240V
Monitor Block Diagram
Keyboard

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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 VGA card.
-Press the power button to turn on the monitor, the power indicator will light up to Green.
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.

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3.3 Adjust the Picture
Main Menu
Press the “Menu” button, the Main Menu should be come on the screen of the monitor
Factory Mode
1、Turn off the monitor. then press AUTO button and MENU button and hold them at the same time, then press power
on, then press “Menu ”button, wait until the OSD menu with Characters “F” come on the Screen of the monitor as
bellow:
2、Push “Menu” to exit OSD menu.
Factory Mode Indicator

19" LCD Color Monitor HP L1940T
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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 Pin layout
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

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4.2 Factory Preset Display Modes
Preset Pixel
Format
Horz Freq
(KHz)
Horz
Polarity Vert Freq (Hz) Vert Polarity
Pixel Clk
(MHz) Source
1 640 x 480 31.469 - 59.940 - 25.175 VGA
2 640 x 480 37.861 - 72.809 - 31.500 VESA
3 640 x 480 37.500 - 75.000 - 31.500 VESA
4 720 x 400 31.469 - 70.087 + 28.322 VGA
5 800 x 600 37.879 + 60.317 + 40.000 VESA
6 800 x 600 48.077 + 72.188 + 50.000 VESA
7 800 x 600 46.875 + 75.000 + 49.500 VESA
8 832 x 624 49.726 ± 74.551 ± 57.284 MAC
9 1024 x 768 48.363 - 60.004 - 65.000 VESA
10 1024 x 768 56.476 - 70.069 - 75.000 VESA
11 1024 x 768 60.023 + 75.029 + 78.750 VESA
12 1152 x 870 68.68 - 75.06 - 100.000 Mac
13 1152 x 900 71.71 - 76.05 - 105.561 Sun
14 1280 x 1024 63.98 + 60.02 + 108.000 VESA
15 1280 x 1024 79.97 + 75.02 + 135.000 VESA
4.3 Power Supply Requirements
PARAMETER RANGE
AC Input Voltage 90 to 265V
AC Input Frequency 47 to 63 Hz
Inrush Current 50A MAX AT 220VAC and 30A AT 120VAC
Leakage Current 5 mA MAX at 120VAC
Power consumption ≤70W

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5. Panel Specification
5.1GeneralFeature
- Wide viewing angle.
- High contrast ratio
- Super fast response time
- High color saturation
- SXGA (1280 x 1024 pixels) resolution
- DE (Data Enable) only mode
- LVDS (Low Voltage Differential Signaling) interface
- RoHS Compliance

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5.2 Optical Characteristics
Test Conditions
Optical Specifications

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6. Monitor Exploded View
.

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7.BlockDiagram
7.1 Scalar Board
Scalar IC NT68663MEFG-128 (Include ADC, OSD, MCU)
(U401)
EEPROM
M24C16-WBN6
(U302)
EEPROM
M24C02
(U403)
H sync
V sync
RGB
DDC_CLK,
DDC_DAT
LCD Interface
(
CN501
)
D-Sub
Connector
(CN201)
Crystal
12MHz
(Y301)
Key Board
Control
(CN402)

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7.2 Inverter / Power Board
EMI filter
Bridge
Rectifier
and Filter
Start Circuit
R904/R910
PWM
Control IC
Transformer
Over
Voltage
Protect
Diode
Rectifier&filter
5V
12V
Start
circuit
OZ9938GN
PWM IC
Feedback
Circuit
LC
resonance
Full bridge
switch circuit
Lamp
ON/OFF
DIM
CON951

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8. Maintainability
Equipments and Tools Requirement
1、Multi-meter.
2、Oscilloscope.
3、Pattern Generator.
4、DDC Tool with an IBM Compatible Computer.
5、Alignment Tool.
6、LCD Color Analyzer.
7、Service Manual.
8、User Manual.

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8.1 Main Board
1. No power
No power
Press power key and look if the
picture is normal
Please reinsert and make sure the
AC of 100-240 is normal
Reinsert or check the
power section
Y301 oscillate waveforms are
normal
Measure CN401 PIN7/8=12V?
PIN10/11=3.3V?
PIN13/14=5V?
Check power section
Replace U401
Replace Y301
OK
Replace U403
OK
OK
NG
NG
NG
NG
NG

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No picture (LED is orange)
No picture
OK
OK
NG
Y301 oscillate waveforms
are normal
Replace Y301
Check if the sync signal from
computer is output and video cable
is connected normally
Input the sync signal of computer, or
change the cable
Replace U401
NG
OK
Key is under control?

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Panel Power Circuit
Replace PANEL
Measure Q403 base is
high level?
Check Q403 and Q402 are broken
or CN301 solder?
Check Correspondent
component.
OK
OK
NG
NG
Y301 oscillate waveforms are
normal
Replace U401
Replace Y301
OK
Replace U403
NG
NG