HP L1940T Series Service Manual
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HP L1940T Series Service Manual

19” lcd monitor
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HP L1940T

SERVICE MANUAL

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.
1

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Summary of Contents for HP L1940T Series

  • Page 1: Service Manual

    HP L1940T SERVICE MANUAL 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...

  • Page 2: Table Of Contents

    HP L1940T 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...

  • Page 3: Revision List

    HP L1940T Revision List Revision Date Revision History TPV Model Feb.-24-06 Initial release T981KMVDBHHPNP Jul.-25-08 Add new BOM T981KGVDBHHPNP...

  • Page 4: Monitor Specification

    HP L1940T 1.Monitor Specifications Driving system TFT Color LCD Panel M190E5-L0A Active Area 376.32(H) x 301.056(V) (19.0") Pixel pitch 0.294( H )x 0.294mm( V ) LCD Panel Viewing Angles(Min / TYP) H:120/140; V:110/130 Response time (typ.) < 8 ms Brightness...

  • Page 5: Lcd Monitor Description

    HP L1940T 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.

  • Page 6: Control Button

    HP L1940T 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.

  • Page 7: Service Mode

    HP L1940T 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”...
  • Page 8 HP L1940T Menu icons Control Icon Brightness Contrast Auto Adjustment Image Control Color Custom Color Language Management OSD Control Information Factory Reset Default Video Input Horizontal Position Vertical Position Clock Clock Phase Power Saver Mode Display Power-On Status Display Sleep Timer...

  • Page 9: Input/Output Specification

    HP L1940T 4. Input/Output Specification 4.1 Input Signal Connector Analog Connector Pinout Mnemonic Signal Mnemonic Signal Red Video +5 V +5 V (from PC) Green Video Sync Ground Blue Video None None DDC Data GND / Cable Detect Horizontal Sync...
  • Page 10 HP L1940T DVI-D Digital Connector Pins Pin. Mnemonic Signal Pin. Mnemonic Signal TX 2 - TMDS Negative differential input, channel 2 TX 3 + TMDS Data 3 + TX 2 + TMDS Positive differential input, channel 2 +5V Power SHLD 2 / 4...

  • Page 11: Factory Preset Display Modes

    HP L1940T 4.2 Factory Preset Display Modes Pixel Horz Freq Horz Vert Pixel Clk Preset Vert Freq (Hz) Source Format (KHz) Polarity Polarity (MHz) 640 x 480 31.469 59.940 25.175 640 x 480 37.861 72.809 31.500 VESA 640 x 480 37.500...

  • Page 12: Panel Specification

    HP L1940T 5. Panel Specification 5.1 General Feature - 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...

  • Page 13: Optical Characteristics

    HP L1940T 5.2 Optical Characteristics Test Conditions Optical Specifications...

  • Page 14: Monitor Exploded View

    HP L1940T 6. Monitor Exploded View...

  • Page 15: Repair Flow Chart

    HP L1940T 7. Repair Flow Chart...
  • Page 16 HP L1940T...
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  • Page 18: Troubleshooting

    HP L1940T 8. Troubleshooting Problem Possible Cause Solution Screen is blank. Power cord is disconnected. Connect the power cord. Power switch is turned Off. Turn on the power. Video cable is improperly connected. Connect the video cableproperly. Screen blanking utility is active.

  • Page 19: Block Diagram

    HP L1940T 9. Block Diagram...

  • Page 20: Schematic

    HP L1940T 10. Schematic 10.1 Main Board...
  • Page 21 HP L1940T...
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  • Page 23 HP L1940T...
  • Page 24 HP L1940T...

  • Page 25: Inverter/Power Board

    HP L1940T 10.2 Power Board (include inverter and power) AC/DC Schematic...
  • Page 26 HP L1940T Inverter Schematic...
  • Page 27 HP L1940T AC/DC Function Block Schematic...
  • Page 28 HP L1940T Inverter Function Block Schematic...

  • Page 29: Key Board

    HP L1940T 10.3 Key Board...
  • Page 30 HP L1940T...

  • Page 31: Pcb Layout

    HP L1940T 11. PCB Layout 11.1 Main Board...

  • Page 32: Inverter/Power Board

    HP L1940T 11.2 Inverter / Power Board...

  • Page 33: Key Board

    HP L1940T 11.3 Key Board...

  • Page 34: Maintainability

    HP L1940T 12. 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.

  • Page 35: White-Balance,Luminance Adjustment

    = 313±20, y = 329 ±20, Y= 150 cd/m 3. Into factory mode of HP L1940T [ Push “Auto Adjust” and “+ (plus)”and hold them at the same time ]+ [ Press power “Power” button untill comes out “windows screen”...
  • Page 36 HP L1940T 2. The chroma 7120 will show x = 313 ±20, y = 329 ±20, Y = 180 cd/m 3. Switch the chroma 7120 l to RGB MODE ( with press “MODE” button to change ) 4. Adjust the RED of color 6500K on factory window until chroma 7120 indicator reached the value R=100 5.

  • Page 37: Check List After Replacing Lcd Main Board

    HP L1940T 14. Check List after replacing LCD Main board Check if white-balance is within the specs after replacing Main board and panel, then re-writing DDC is necessary. 14.1 Check white-balance The white-balance value for each common color temperature: 9300 º K: x=283± 20 ; y = 297± 20;...
  • Page 38 HP L1940T 2. Select the DDC2Bi as the communication channel. As shown in Fig. 12. 3. Click OK button to confirm your selection. 4. Click icon (Read EDID function) to read DDC EDID data from monitor. The EDID codes will display on screen as...
  • Page 39 HP L1940T Step 3: Modify DDC data (verify EDID version, week, year) Click (new function) icon from the tool bar, bring up Step 1 of 9 as shown in Fig. 14 . EDID4.6 DDC application provides the function selection and text change (select & fill out)from Step 1 to Step 9.
  • Page 40 HP L1940T 2. Click Next , bring up Fig.16. 3. Click Next , bring up Fig.17.
  • Page 41 HP L1940T 4. Click Next , bring up Fig.18. 5. Click Next , bring up Fig.19.
  • Page 42 HP L1940T 6. Click Next , bring up Fig. 20. In this step, please confirm the Descriptor Data Type is Monitor Range Limits, and all the items are same as below. 7. Click Next , bring up Fig. 21.
  • Page 43 HP L1940T 8. Click Next , bring up Fig. 22. - Click Finish to exit the Step window. - Serial number can be filled up at this moment (for example,TWP318Q001). NOTE: You must modify the Serial NO. In step 9, otherwise the Serial NO. In OSD Couldn't be modified correctly.
  • Page 44 HP L1940T 2. Access 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 until the OSD menu with Characters "F"...
  • Page 45 HP L1940T Sometimes, you may need to save DDC data as a text file for using in other IC chip. To save DDC data, follow the steps below: 1. Click (Save) icon (or click "file"-> "save as") from the tool bar and give a file name as shown in Fig. 25. The file type is EDID46 file (*.ddc) which can be open in WordPad.
  • Page 46 HP L1940T Step 2: Read DDC data from monitor 1. Click icon as shown in Fig. 11 from the tool bar to bring up the Channels "Configuration Setup" windows as shown in Fig. 2. Select the DDC2Bi as the communication channel. As shown in Fig. 29.
  • Page 47 HP L1940T 3. Click OK button to confirm your selection. 4. Click icon (Read EDID function) to read DDC EDID data from monitor. The EDID codes will display on screen as shown in Fig. 30. Step 3: Modify DDC data (verify EDID version, week, year) Click (new function) icon from the tool bar, bring up Step 1 of 9 as shown in Fig.
  • Page 48 HP L1940T 2. Click Next , bring up Fig. 33. Fig. 33 Fig. 34 3. Click Next , bring up Fig. 34. 4. Click Next , bring up Fig. 35. 5. Click Next , bring up Fig. 36. 6. Click Next , bring up Fig. 37.
  • Page 49 HP L1940T 8. Click Next , bring up Fig. 39. - Click Finish to exit the Step window. - Serial number can be filled up at this moment (for example, TWP318Q001). NOTE: You must modify the Serial NO. In step 9, otherwise the Serial NO. In OSD Couldn't be modified correctly.
  • Page 50 HP L1940T 3) Push Menu to exit OSD menu. 3. Click (Write EDID) icon from the tool bar to write DDC data.Then the screen will be black for 5-10 seconds, when the screen recovers ,DDC data will be finished Writing.
  • Page 51 HP L1940T 1. Click (Save) icon (or click "file"-> "save as") from the tool bar and give a file name as shown in Fig. 46. The file type is EDID46 file (*.ddc) which can be open in WordPad. By using WordPad, the texts of DDC data & table (128 bytes, hex code) can be modified.

  • Page 52: Edid Content

    HP L1940T 15. EDID Content Analog 16 : 32 : 48 : 64 : 80 : 96 : 112: Digital 16 : 32 : 48 : 64 : 80 : 96 : 112:...
  • Page 53 HP L1940T 16. BOM List T981KMVDBHHPNP Location Part No. Description Remark 034G6402 EY B REAR COVER 037G6057 2 HINGE 040G 58169016A TCO'03 LABEL 041G7800690A16 QSG FOR EUR 041G7800690B01 SCREEN RESOLUTION 044G3231 15571 EVA WASHER 044G3957 1 CUSHION-R 044G3957 2 CUSHION-L...
  • Page 54 HP L1940T 015G6343 1 MAIN FRAME-LPL 052G6025 11976 INSULATION PLATE 052G6025 11981 MYLAR 095G8P14 7505 CBLE-267 7/330/7-267 AWG28 Q85G 583611 GASKET_ALUMINIUM FOIL E750L 750GLM90E5A11Z PANEL LCD 19" E5-L05 C1 D CMO CBPC980KMVHPP CONVERSION BOARD 040G 45762412B CBPC LABEL 1503 033G3802 7...
  • Page 55 HP L1940T 7202 056G1133 34 M24C02-WMN6TP 7203 056G1133 34 M24C02-WMN6TP 7301 056G1133519MP3 IC AT49BV002ANT-70JU ATMEL 7210 056G4LCX 14 PH IC 74LVC14APW PHILIPS 7210 056G4LCX 14 ST IC SM 74LCX14T 7210 056G4LVC 14 TI IC SN74LVC14APWR TSSOP-14 TI 7501 057G 420519 T...
  • Page 56 HP L1940T 3224 061G0603101 RST CHIPR 100 OHM +-5% 1/10W 3223 061G0603101 RST CHIPR 100 OHM +-5% 1/10W 3219 061G0603101 RST CHIPR 100 OHM +-5% 1/10W 3218 061G0603101 RST CHIPR 100 OHM +-5% 1/10W 3217 061G0603101 RST CHIPR 100 OHM +-5% 1/10W...
  • Page 57 HP L1940T 3623 061G0603105 RST CHIPR 1M OHM +-5% 1/10W 3615 061G0603105 RST CHIPR 1M OHM +-5% 1/10W 3621 061G0603105 RST CHIPR 1M OHM +-5% 1/10W 3404 061G0603121 RST CHIPR 120 OHM +-5% 1/10W 3405 061G0603121 RST CHIPR 120 OHM +-5% 1/10W...
  • Page 58 HP L1940T 2229 065G0603103 32 CAP CHIP 0603 0.01UF K 50V X7R 2452 065G0603103 32 CAP CHIP 0603 0.01UF K 50V X7R 2453 065G0603103 32 CAP CHIP 0603 0.01UF K 50V X7R 2454 065G0603103 32 CAP CHIP 0603 0.01UF K 50V X7R...
  • Page 59 HP L1940T 2606 065G0603104 12 CER2 0603 X7R 16V 100N P 2605 065G0603104 12 CER2 0603 X7R 16V 100N P 2604 065G0603104 12 CER2 0603 X7R 16V 100N P 2603 065G0603104 12 CER2 0603 X7R 16V 100N P 2531 065G0603104 12...
  • Page 60 HP L1940T 2620 065G0603180 31 CAP CC 18PF 50V J NPO 0603 2621 065G0603180 31 CAP CC 18PF 50V J NPO 0603 2518 065G0603221 31 CER1 0603 NP0 50V 220P P 2219 065G0603221 31 CER1 0603 NP0 50V 220P P...
  • Page 61 HP L1940T 2439 067G411F1003XT CAP S105℃ 10UF M 16V 2439 067G411F1003XT CAP S105℃ 10UF M 16V 2426 067G411F1003XT CAP S105℃ 10UF M 16V 2426 067G411F1003XT CAP S105℃ 10UF M 16V 2425 067G411F1003XT CAP S105℃ 10UF M 16V 2425 067G411F1003XT CAP S105℃ 10UF M 16V...
  • Page 62 HP L1940T 5601 071G 57K101 B CHIP BEAD HCB3216KF-101T30 BULLWILL 5605 071G 57K101 B CHIP BEAD HCB3216KF-101T30 BULLWILL 5606 071G 57K101 B CHIP BEAD HCB3216KF-101T30 BULLWILL 5607 071G 57K101 B CHIP BEAD HCB3216KF-101T30 BULLWILL 5603 071L 56121 TA 0805 120 OHM 3A...
  • Page 63 HP L1940T 1601 093G 22S51B H CRYSTAL 12.00000MHZ/32PH/HC-49-USM RISHA 6209 093G 39S 66 DIO REG SM BZX84-C5V1 (PHSE)R 6209 093G 39S 66 DIO REG SM BZX84-C5V1 (PHSE)R 6221 093G 64S3PH BAS32L 6222 093G 64S3PH BAS32L 715G1854 1 MAIN BOARD PCB...

  • Page 64: Bom List

    HP L1940T Diversity of T56CM4DKABHPNE compared with T54VM4DCABHANE Location Part No. Description Remark CONDUCTIVE TAPE 45MM *25MM 052G 1207 A *0.08MM 052G 1218 A SILVER E089 089G179J 30712 FFC CABLE KOTL E089 089G179P 30712 FFC 30/149/30 PITCH 1.0MM 2nd source...

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