HP L1940 User manual

Horizontal frequencies
30-83kHz
Service
Service
Service
TABLE OF CONTENTS
Published by BCU Monitors Printed in Suzhou Copyright reserved Subject to modification K Oct. 15 2004
Description Page
Important Safety Notice---- ------------------------------ 2
Technical Data ------------------------------------------3~4
Warning Message------------------------------------------7
Lock/unlock,Aging,Service/Factory mode------------8
Definition of pixel defects-------------------------------12
Instalation/On Screen Display------------------------5~6
Flat panel adjust--------------------------------------------9
Mechanical Instructions----------------------------10~11
Electrical instruction--------------------------------13~14
DDC Instructions-------------------------------------15~21
Failure mode of panel------------------------------------22
Safety Test Requirments--------------------------------23
ISP CABLE FOR CPU-------------------------------24~26
Description Page
Repair tips ------------------------------------------------27
Color adjustment----------------------------------------28
Repair Flow chart/Trouble shooting-------------29~32
Block Diagram---------------------------------------33~34
Control Diagram & C.B.A.------------------------------43
Power Diagram & C.B.A.--------------------------44~47
Exploded View------------------------------------------- 48
Spare/recommended parts list------------------49~50
General product specification--------------------51~78
DDC DATA -------------------------------------------79~80
Different parts list----------------------------------------81
Scaler Diagram&C.B.A.---------------------------36~42
Wiring Diagram -----------------------------------------35
REFER TO BACK COVER FOR IMPORTANT SAFETY GUIDELINES
CAUTION: USE A SEPARATE ISOLATION TRANSFORMER FOR THIS UNIT WHEN SERVICING.
ANY PERSON ATTEMPTING TO SERVICE THIS CHASSIS MUST FAMILIARIZE HIMSELF WITH THE CHASSIS
AND BE AWARE OF THE NECESSARY SAFETY PRECAUTIONS TO BE USED WHEN SERVICING ELECTRONIC
EQUIPMENT CONTAINING HIGH VOLTAGES.
SAFETY NOTICE
SH4 HP L1940
GB 3138 106 10428
19" LCD Colour Monitor
EJ6B50/02
EJ6B50/69
EJ6B50/76

Important Safety Notice
2HP L1940
Go to cover page
Proper service and repair isimportant to the safe, reliable
operation of all HPConsumer Electronics Company**
Equipment. The service procedures recommended by HP and
described in this service manual are effective methods of
performing service operations. Some ofthese service
operations require the use of tools specially designed for the
purpose. The special tools should be used when and as
recommended.
It is important to note that this manual contains various
CAUTIONS and NOTICES which should be carefully read in
order to minimize the risk of personal injury to service
personnel. The possibility exists that improper service
methods may damage the equipment. It is also important to
understand that these CAUTIONS and NOTICES ARE NOT
EXHAUSTIVE. HP could not possibly know, evaluate and
advise the service trade of all conceivable ways in which
service might be done or of the possible hazardous
consequences of each way. Consequently, HP has not
undertaken any such broad evaluation. Accordingly, a
servicer who uses a service procedure or tool which is not
recommended by HP must first satisfy himself thoroughly that
neither his safety nor the safe operation of the equipment will
be jeopardized by the service method selected.
* * Hereafter throughout this manual, HP Consumer
Electronics Company will bereferred to as HP.
Critical components having special safety characteristics are
identified with a bythe Ref. No. inthe parts list and
enclosed within a broken line*
(where several critical components are grouped in one area)
along with the safety symbol on the schematics or
exploded views.
Use of substitute replacement parts which do not have the
same specified safety characteristics may create shock, fire,
or other hazards.
Under no circumstances should the original design be
modified or altered without written permission from Philips.
Philips assumes no liability, express or implied, arising out of
any unauthorized modification of design.
Servicer assumes all liability.
* Broken Line
WARNING
Take care during handling the LCD module with backlight
unit
- Must mount the moduleusing mounting holes arranged infour
corners.
- Do not press onthe panel, edge of theframe strongly or electric
shock as this will result in damage to the screen.
- Do not scratch orpress on the panel withany sharp objects, such
as pencil or pen asthis may result in damage to the panel.
- Protect the module fromthe ESD as it maydamage the electronic
circuit (C-MOS).
- Make certain that treatment person s body are grounded through
wrist band.
- Do not leave themodule in high temperature andin areas of high
humidity for a long time.
- Avoid contact with water as it may ashort circuit within the module.
- If the surface ofpanel become dirty, please wipe it off with a soft
material. (Cleaning with a dirty or rough cloth may damage the
panel.)
FOR PRODUCTS CONTAINING LASER :
DANGER- Invisible laser radiation when open.
AVOID DIRECT EXPOSURE TO BEAM.
CAUTION- Use of controls or adjustments or
performance of procedures other than
those specified herein may result in
hazardous radiation exposure.
CAUTION- The use of optical instruments with this
product will increase eye hazard.
TO ENSURE THE CONTINUED RELIABILITY OF THIS
PRODUCT, USE ONLY ORIGINAL MANUFACTURER'S
REPLACEMENT PARTS, WHICH ARE LISTED WITH THEIR PART
NUMBERS IN THE PARTS LIST SECTION OF THIS
SERVICE MANUAL.

3
Technical Data
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HP L1940
Pin Assignment
InputDVI-D connector pin
LCDPanel
Type NR. :LM190E02_A5 (LPL)
Numberof Pixels. : 1280 (H) x 1024 (V)
Physical Size. : 404.2(H)*330.0(V)*20.0(D)mm
Pixel Pitch. : 0.294 x 0.294 mm
Color pixel arrangement. : RGB stripes arrangement
SupportColor. : 8 bit (16.7M Colors)
Display Mode. : Transmissive Mode,Normally Black
Backlight. : CCFL edge light system
Active area. (WxH). : 376.32(H) x 301.056(V)mm (19 diagonal)
Viewing Angle. : Vertical 176 degree, Horizontal 176 degree
(CR=10)
Contrast ratio. : 500:1
Luminance. : 250 cd/m2(Typ)
Scanning frequencies
H-Frequency. : 30K -83 K Hz
V-Frequency. : 56 -76 Hz
Powerinput. : 90-265 VAC, 50/60 ±2Hz
Powerinput. : 90-265 VAC, 50/60 ±2Hz
The inputsignalscan be applied in twodifferent modes:
1). VESA Analog
The videoinputconsists ofred, green, and blue signals. The video
signals areanalog levels, where0Vcorr
esponds toblack and 700mVis
the maximumsignalamplitude. Inputimpedanceofvideopinsis75ohm
+-1%. The VESA VSISspecification states the videovoltages shall be
700 mV+10%/-5% with 12% for the overshoot. The apability of sync
signal inputs shall include separate sync.inputimpedance: 2k2 ohms The
signals are defined as follow:
Separate sync3.3Vand5volt TTL level ,Positive/Negative
2). Intel DVI Digital
Inputsignal:Four channel TMDS signals. The digital interfaceshall
be comprised of2electrical layercomponent: a TMDSinterfacefor low-
voltage differential serial encoding of the digital display data(Panel Link
compliant) and a DDC2B electrical interface. Refertothe Digital Display
Working Group(DDWG) document, Digital Visual Interface(DVI)
Specification, Revision1.0 for the exactrequirements.
Unit dimension / Weight
Set dimension(incl. pedestal) : 413(W) * 477(H) * 265(D)mm
Net weight. : 8.4 kg
Tilt and swivel base
Basicbase: tilt angle : -5°to+35 °(operation)
swivel rotation:±90°
Shipping dimension/Weight
Carton dimension. : 524(W) * 239(D) * 513(H) mm
Gross weight. : 10 Kg
Susceptibility ofdisplay toexternal environment
Temperature Ranges
Operating Temperature(Independent of altitude) : 5°Ct
o35°C.
Non-Operating Temperature(Independent of altitude) : -20°Cto60°C.
Humidity
Operating (non-condensing) : 20% to80%
Non-Operating (38.7°Cmaximumwetbulb temperature) : 5% to90%
Altitude
Operating 0 to12,000 feet [3,658 m].Equivalent to14.7 to10.1 psia.
Non-Operating0to40,000 feet [12,192 m]. Equivalent to14.7 to4.4 psia
Red videoinput
Green videoinput
Blue videoinput
GND
Cable detect
Red videoGND
Green videoGND
Blue videoGND
DDC +3.3VOR +5V
GND
GND
Serial data line (SDA)
H-sync
V-sync
Data clock line (SCL)
7
8
6
5
4
3
2
19
10
11
12
13
14
15
Pin No.Pin No. Assignment Assignment
Pin No.Description
1T.M.D.S data2-
2T.M.D.S data2+
3T.M.D.S data2 shield
4Noconnect
5Noconnect
6DDCclock
7DDCdata
8Noconnect
9T.M.D.S data1-
10 T.M.D.S data1+
11 T.M.D.S data1 shield
12 Noconnect
13 Noconnect
14 +5Vpower
15 Ground (for +3.3V)-Cable detect
16 Hotplug detect
17 T.M.D.S data0-
18 T.M.D.S data0+
19 T.M.D.S data0 shield
20 Noconnect
21 Noconnect
22 T.M.D.S clockshield
23 T.M.D.S clock+
24 T.M.D.S clock-

Technical Data(Continued)
4
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This monitor is ENERGY STAR compliant.
this product meets the ENERGY STAR guidelines for energy
Data Storage R
R
Efficiency
ENERGY STAR is a U.S. registered mark. AS AN ENERGY STAR
PARTNER, DELL Computer Corporation HAS DETERMINED THAT
THIS PRODUCT MEETS THE ENERGY STAR GUIDELINES FOR
ENERGY EFFICIENCY.
R
HP L1940
Power management
The power consumption and the status indication of the set with power management function
are as follows,
STATUS H-sync V-sync Video Power LED indicator
On On On Active < 70W Green LCD
(*Note1)
Stand-by Off On Blanked < 2W
Amber LCD
(*Note2)
Suspend On Off Blanked < 2W
Amber LCD
(*Note2)
Off Off Off Blanked < 2W Amber LCD
(*Note2)
DC Switch off N/A N/A N / A < 1W Off (*Note 2)
Note 1: Included two active external USB devices
Note 2: Measurement is required to connect PC via USB 2.0 upstream cable and be
without any external USB devices. The operating system is required to be
Windows XP , and USB interface of PC shall conform to USB 2.0 compliance.
Display identification
Analog DDC
In accordance with VESA Display Channel Standard V1.0 and having DDC-2B capability.
Digital DDC
In accordance with DVI requirement (DDWG digital Visual Interface revision 1.0) use DDC-2B
and EDID 3.0 structure 2.0
Factory preset modes (15 modes)
# Resolution H-Frequency
(Hz)
Pixel rate
(MHz)
V-Frequency
(Hz)
Comment
1 640X480 31.469K 25.175 59.940 VGA
2 640X480 37.861K 31.5 72.809 VESA
3 640X480 37.5K 31.501 75 VESA
4 720X400 31.469K 28.322 70.087 VGA
5 800X600 37.879K 40 60.317 VESA
6 800X600 48.077K 50 72.188Hz VESA
7 800X600 46.875K 49.498 75Hz VESA
8 832X624 49.726K 57.284 74.551Hz MAC
9 1024X768 48.363K 65 60.004Hz VESA
10 1024X768 56.476K 75 70.069Hz VESA
11 1024X768 60.023K 78.75 75.029Hz VESA
12 1152X870 68.68K 100 75.06Hz MAC
13 1152X900 71.71K 108 76.05Hz SUN
14 1280X1024 63.98K 108 60.02Hz VESA
15 1280X1024 79.97K 135 75.02Hz VESA

Installation 5
HP L1940
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Connecting to PC
When two computers are connected, you will need to set the
Video Input Select on the on-screen display (OSD) menu to
specify which monitor input has priority.
1. Place the monitor in a convenient, well-ventilated location
Near your computer.
2. Connect the monitor signal cable into the correct video
connector (VGA or DVI-D) on the back of the monitor and into
the corresponding video connector on the rear panel of the
computer.
Your computer must have a DVI -compatible graphics card
installed for use with the DVI-D cable. When connecting the
DVI-D signal cable to the DVI connector on the monitor, connect
the other end of the DVI-D cable to the DVI connector on the
Computer.
3. Connect one end of the power cable to the back of the monitor,
and the other end to an electrical wall outlet.
Warnning:To reduce the risk of electric shock or damage to
your equipment:
1. Do not disable the power cord grounding plug. The grounding
plug is an important safety feature.
2. Plug the power cord into a grounded (earthed) electrical outlet
that is easily accessible at all times.
3. Disconnect power from the monitor by unplugging the power
cord from the electrical outlet.
Front control panel
Identifying Rear Panel Components
1234 5
No. Component Function
AC power
connector
Connects the AC power cord to the monitor.
USB downstream
connectors
Connects optional USB devices to the monitor.
USB upstream Connects the USB cable to the host (computer
connector or another USB hub).
DVI connector
(available on
select models)
Connects the DVI-D signal cable to the monitor.
VGA connector Connects the VGA cable to the monitor.
1
2
3
4
5
4. Do not place anything on power cords or cables. Arrange them
so that no one may accidentally step on or trip over them. Do not
pull on a cord or cable. When unplugging from the electrical
outlet, grasp the cord by the plug.
12345
No. Component Function
1
2
3
4
5
Auto Adjust Activates the auto adjustment feature for
optimum image.
Menu Opens the On-Screen Display (OSD) menu.
-(Minus) If OSD is on, press to navigate backward
through the OSD menu features and
decrease adjustment levels.
If OSD is off, press to enable the DVI
signal input(available on select models)
+ (Plus) If OSD is on, press to navigate forward
through the OSD menu features and increase
adjustment levels.
If OSD is off, press to enable the VGA signal
input.
Power Turns the monitor on or off.

On Screen Display
6
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HP L1940
Advanced osd service mode configuration
Analog Mode Menu
Menu Level 1 Menu Level 2
Brightness ADJ Scale
Contrast ADJ Scale
Auto Adjustment (Adjusting message)
Advanced Menu
Exit
Digital Mode Menu
Menu Level 1 Menu Level 2
Brightness ADJ Scale
Contrast ADJ Scale
Advanced Menu
Exit
Analog Mode Menu
Menu Level 1 Menu Level 2 Menu Level 3 Factory Reset?
Brightness ADJ Scale Y (FP=90)
Contrast ADJ Scale Y (FD=80)
Image Control Auto Adjustment (Adjusting
message)
Y(noFD)
Horizontal Position ADJ Scale Y (no FD)
Vertical Position ADJ Scale Y (no FD)
Clock ADJ Scale Y (no FD)
Clock Phase ADJ Scale Y (no FD)
Cancel
Save and Return
Color 9300 K
6500 K Y(FD)
Custom Color Custom Color
ADJ
sRGB
Cancel
Save and Return
Service Display Hours N
Reset Total Hours Confirm Reset N
Reset Backlight Hours Confirm Reset N
Copy All Settings Confirm Reset N
Recall All Settings Confirm Reset N
Display White Block N
Unlock EDID Write
Cancel N
Save and Return N
Management Power Saver On / Off
Selection
N(FD=ON)
Power On Recall On / Off
Selection
N(FD=ON)
Mode Display On / Off
Selection
N (FD=OFF)
Power-On Status
Display
On / Off
Selection
N(FD=ON)
Sleep Timer Timer Set Menu N (FD=0;OFF)
Default Video Input -Analog - VGA N(FD=DVI)
-Digital - DVI
Serial Number Display monitor
s/n
Basic Menu N(FD=Basic)
Cancel
Save and Return
OSD Control Horizontal OSD Position ADJ Scale N (FD=50)
Vertical OSD Position ADJ Scale N (FD=50)
OSD Timeout ADJ Scale N (FD=30)
Cancel
Save and Return
Information Current Settings:
Recommended Settings:
Serial Number:
Total Hours:
Backlight Hours:
Exit
Factory Reset Yes
No
Exit
Digital Mode Menu
Menu Level 1 Menu Level 2 Menu Level 3 Factory Reset?
Brightness ADJ Scale Y (FP=90)
Contrast ADJ Scale Y (FD=80)
Color 9300 K
6500 K Y(FD)
Custom Color Custom Color
ADJ
sRGB
Cancel
Save and Return
Service Display Hours
Reset Total Hours Confirm Reset N
Reset Backlight Hours Confirm Reset N
Copy All Settings Confirm Reset N
Recall All Settings Confirm Reset N
Display White Block N
Unlock EDID Write
Cancel
Save and Return
Management Power Saver On / Off
Selection
N(FD=ON)
Power On Recall On / Off
Selection
N(FD=ON)
Mode Display On / Off
Selection
N(FD=OFF)
Power-On Status
Display
On / Off
Selection
N(FD=ON)
Sleep Timer Timer Set Menu N (FD=0;OFF)
Default Video Input -Analog - VGA N (FD = DVI)
-Digital - DVI
Serial Number Display monitor
s/n
Basic Menu N(FD=Basic)
Cancel
Save and Return
OSD Control Horizontal OSD Position ADJ Scale N (FD=50)
Vertical OSD Position ADJ Scale N (FD=50)
OSD Timeout ADJ Scale N (FD=30)
Cancel
Save and Return
Information Current Settings:
Recommended Settings:
Serial Number:
Total Hours:
Backlight Hours:
Exit
Factory Reset Yes
No
Exit
basic osd menu levels

Warning Message
7
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HP L1940
Warning Message Table
Item Attention Signals Display Time Condition
1 Input Signal out of Range See power savertable
2 No Input Signal See power savertable
3 Going to Sleep See power savertable
4 Adjusting...... Auto key or OSD menu function
5 OSD Lock out 3secs Push menu key for 10 sec then display 3 sec WM OSD
Lock out
6
7 Status AC/DC on and "Power-On Status Display is on
Check Video Cable
10secs
See power savertable
Power Saver Table
Power Saver - On Power Saver - Off Note
Quit signal with
cable
1. System blank and show WM
"Going to Sleep" 3 sec then sleep.
1. System blank and show moving
WM "No Input Signal"always.
Disconnect cable 1. System blank and show WM
"Check Video Cable"60 sec.
1. System blank and show WM
"Check Video Cable" 10
2.Show WM "Going to Sleep" 3 sec
then sleep.
then repeat item 1 to 2.
sec then moving always.
Out of range - 1 1. System blank and show WM
"Check Video Cable" 20 sec then
moving about 30 sec After moving
3. If push any key in sleep mode,
then repeat item 1to 2.
1. System blank and show moving
WM"In Put Signal out of Range"
always.
H<29.5 or
H>92 or
90>H>82.5 or
V<49 or V>87
or Vtotal>=120
0
Out of range - 2 1. Show moving WM"Input Signal
out of Range" always. 85Hz
3. If push any key in sleep mode,
WM 50 sec.
2. The backlit turn off.
1. System blank and show WM
"Check Video Cable" 20 sec then
moving about 30 sec After moving
3. If push any key in sleep mode,
then repeat item 1to 2.
WM 50 sec.
2. The backlit turn off.

8
Lock/Unlock,Aging, Service/Factory Mode
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HP L1940
Front control panel
ToLock/Unlock OSD function
AGING MODE
Nosignal input,power off -> on ,then Into thefactorymode,,afull
white pattern will bedisplayon thescreen asFig.1&Fig.2 insteadof
power savingmode.Inother words, thepower savingfunction will be
disable inthefactorymode.Supplyone signal for leavingagingmode.
SERVICE MODE
Press andholdthe"Menu" button ,power off -> on"Power",then
Into theservice mode.Press "Menu" button to bringupOSD
menufor confirmation asbelow:
Access FactoryMode
Factorymenu
Cursor can moveongraycolor area
BL : Blacklevel value
SUB-BRI : Brightness value range(MinMax)
SUB-CON : Contrastvalue range(MinMid Max)
SRGB-B : Brightness of sRGB(Reserved)
SRGB-C : Contrastof sRGB(Reserved)
AUTO-SUB: TodoAuto color function when
push "Up"keyinwhite pattern
Panel Type:Ifset this to 1,2,3,4,5 then system
will force panel type to LG(QDI), CPT orAU).
Set to other valuewill auto detect panel basedon
panel hardware.
SCALER : Read/Write scaler register
NVRAM : Read/Write eepromaddress
12345
Auto AdjustMenu-(Minus) +(Plus) Power
OSD LockTheOSD can beenabledor disabledbypressingand
holdingtheMenubutton on thefront panel for 10 seconds. If the
OSD is locked, thewarningmessage"OSD Lock" displays for
ten seconds.
If theOSD is locked, press andholdtheMenubutton for 10
seconds to unlocktheOSD.
If theOSDisunlocked, press andholdtheMenubutton for 10
seconds to locktheOSD.
1). Turn off monitor.
2). [Push "Auto Adjust"and
"+(plus)"andholdthemat thesame
time]+[Press power "Power "
button untill comesout"Windows
screen"] => then release all button,
then press "Menu" button,waituntil
theOSD menuwithCharacters"F"
(rightOSD menu) comeonthe
Screen ofthemonitor
Fig.1 Fig.2

Flat Panel Adjust 9
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HP ADJUSTMENT PATTERN.EXE
VERSION: 2.00 Rev A
OPERATING SYSTEM(S):
Microsoft Windows 98
Microsoft Windows Millennium Edition (ME)
Microsoft Windows 2000
Microsoft Windows XP 32-bit Personal
Microsoft Windows XP 32-bit Professional
DESCRIPTION: This CD contains the HP Auto-Adjustment utility, which is a
single pattern program designed to help improve the picture quality of your HP
flat panel monitor.
Note: Do not use the following procedure if your flat panel monitor is using a
DVI connector option.
To use the Adjustment pattern with your flat panel monitor:
1. Execute the auto-adjust function from the OSD main menu.
2. If the result is not satisfactory, start the "Adjustment pattern.exe" program
and repeat step 1.
Image quality characteristics that can be improved:
- Fuzzy or unclear focus
- Ghosting, streaking or shadowing effects
- Faint vertical bars
- Thin horizontal scrolling lines
- Centering the picture
Note: To achieve optimal picture performance, it is recommended that you
always set the operating system display mode to your flat panel's native
resolution. See list below for reference.
14in. and 15in. flat panels = 1024x768
17in., 18in. and 19in. flat panels = 1280x1024
20in. and 21in. flat panels = 1600x1200
HP L1940

Mechanical Instruction
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10
HP L1940
Front view
Back view
Step 1. Remove the stand.
Remove the four screws as Fig.3
Fig.3
Fig.4
Fig.2
Fig.1
Step 2. Remove the Back cover as Fig.5~8.
a.
b. Use thin "I" type screwdriver to open 4 clicks on bottom
side as Fig.5
c.
Remove the four screws on the left and right sides as Fig.4
Use thin "I" type screwdriver to open 3 clicks on right
side as Fig.6
e. Use thin "I" type screwdriver to open 3 clicks on left
side as Fig.7
f. Remove the front cover as Fig.8
g. Remove the back cover as Fig.9 ,then remove the 8 screws
Fig.5
Fig.6
Fig.7
Fig.8
Step 3. Remove the Scaler and Power board.
Remove the 9 screws and disconnect the 7 cables as Fig. 10
Fig.9
Fig. 10