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.
HP L1940T Table of Contents Table of Contents ------------------------------------------------------------------------------------------------------------------------ 02 Revision List ------------------------------------------------------------------------------------------------------------------------------ 03 1.Monitor Specification ----------------------------------------------------------------------------------------------------------------04 2.
HP L1940T Revision List Revision Date Revision History TPV Model A00 Feb.-24-06 Initial release T981KMVDBHHPNP A01 Jul.
HP L1940T 1.Monitor Specifications LCD Panel Input 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 ) Viewing Angles(Min / TYP) H:120/140; V:110/130 Response time (typ.) < 8 ms Brightness 200 nits Contrast 450:1 Video Analog /Digital Sync. Type H/V TTL H-Frequency 30kHz – 83kHz V-Frequency 56Hz – 76Hz Display Colors Over 16 million Colors Pixel Clock 140MHz Max.
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. Monitor Block Diagram Flat Panel and CCFT Drive.
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. 2、If OSD is off, press to enable the DVI signal input (available on select models).
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.
HP L1940T Menu icons No.
HP L1940T 4. Input/Output Specification 4.
HP L1940T DVI-D Digital Connector Pins Pin. Mnemonic Signal Pin.
HP L1940T 4.2 Factory Preset Display Modes Pixel Horz Freq Horz Vert Pixel Clk Format (KHz) Polarity Polarity (MHz) 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.
HP L1940T 5. Panel Specification 5.1 General Feature - Wide viewing angle.
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HP L1940T 6. Monitor Exploded View .
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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. Depress any key on the keyboard or moveThe mouse to inactivate the screen blanking Utility. Image appears.blurred, indistinct, Brightness and contrast are too low or too dark.
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HP L1940T 10. Schematic 10.
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HP L1940T Inverter Schematic 26
HP L1940T AC/DC Function Block Schematic 27
HP L1940T Inverter Function Block Schematic 28
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HP L1940T 11. PCB Layout 11.
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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.
HP L1940T 13. White-Balance,Luminance Adjustment Approximately 30 minutes should be allowed for warm up before proceeding White-Balance adjustment. 1. How to do the Chroma-7120 MEM .Channel setting A. Reference to chroma 7120 user guide B. Use “ SC” key and “ NEXT” key to modify xyY value and use “ID” key to modify the TEXT description Following is the procedure to do white-balance adjust 2. Setting the color temp. You want A. 9300 color: 9300 color temp.
HP L1940T 2. The chroma 7120 will show x = 313 ±20, y = 329 ±20, Y = 180 cd/m2 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. Adjust the GREEN of color 6500K on factory window until chroma 7120 indicator reached the value G=100 6. Adjust the BLUE of color 6500K on factory window until chroma 7120 indicator reached the value B=100 7.
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; 6500K: x = 313± 20 ; y = 329 ± 20; sRGB: x = 313± 20 ; y = 329 ± 20; The color temperature value above must be up to the situation of x
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 shown in Fig. 13.
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. Step 4: Modify DDC data (Monitor Serial No.) 1. Click Next , bring up Fig. 15.
HP L1940T 2. Click Next , bring up Fig.16. 3. Click Next , bring up Fig.17.
HP L1940T 4. Click Next , bring up Fig.18. 5. Click Next , bring up Fig.19.
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.
HP L1940T T 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. Step 5: Write DDC data 1. Configuration should be as Fig. 23. And press OK.
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" (below OSD menu) come on the Screen of the monitor (see Fig. 24). 3) Push Menu to exit OSD menu. 4). Click (Write EDID) icon from the tool bar to write DDC data.
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. By using WordPad, the texts of DDC data & table (128 bytes, hex code) can be modified. If DDC TEXTS & HEX Table ar completely correct, it can be saved as .
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. 28. 2. Select the DDC2Bi as the communication channel. As shown in Fig. 29.
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. 31 . EDID46 DDC application provides the function selection and text change (select & fill out) from Step 1 to Step 9. Step 4: Modify DDC data (Monitor Serial No.) 1.
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. 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. 38.
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. Step 5: Write DDC data 1. Configuration should be as Fig. 40. And press OK. 2. Access Factory Mode 1). Turn off monitor. 2).
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. 4. Confirm Serial Number in User Mode 1) Press the "Power " button to turn off the monitor. Press the button again to turn on the monitor. 2) Press the" Menu " button to bring up the OSD main menu.
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. If DDC TEXTS & HEX Table ar completely correct, it can be saved as *.ddc flie to re-load it into DDC IC for DDC Data application. 2. Click Save. Step 7: Exit DDC program Pull down the File menu and select Exit as shown in Fig. 44.
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HP L1940T 16. BOM List T981KMVDBHHPNP Location Part No.
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 750GLM90E5A11Z PANEL LCD 19" E5-L05 C1 D CMO CBPC980KMVHPP CONVERSION BOARD 040G 45762412B CBPC LABEL 1503 033G3802 7 WAFER EH 7 1502 033G3802 14 14P/2.0MM 7302 056G11332PHMP1 IC M24C16-WBN6 (ST00)L 7608 056G1133521LP6 IC AT93C46-10PI-2.
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 BC857C 7502 057G 420519 T BC857C 7503 057G 7601PH TRA SIG SM MUN2211J(ONSE)R 7503 057G 7602PH TRA PDTC114EK SC-59 PHILIPS 7503 057G 760500KEC TRA KRC102S KEC 7504 057G 7631PH FET POW SM SI5441DC(VISH)R 3620 061G
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 3216 061G0603101 RST CHIPR 100 OHM +-5% 1/10W 3212 061G0603101 RST CHIPR 100 OHM +-5% 1/10W 3211 061G0603101 RST CHIPR 100 OHM +-5% 1/10W 3210 061G0603101 RST CHIPR 100 OHM +-5% 1/10W 3207 061G0603101 RST CHIPR 100 OHM +-5% 1/10W 3206 061G06
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 3406 061G0603121 RST CHIPR 120 OHM +-5% 1/10W 3610 061G0603152 RST CHIPR 1.
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 2455 065G0603103 32 CAP CHIP 0603 0.
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 CER2 0603 X7R 16V 100N P 2529 065G0603104 12 CER2 0603 X7R 16V 100N P 2525 065G0603104 12 CER2 0603 X7R 16V 100N P 2523 065G0603104 12 CER2 0603 X7R 16V 100N P 2521 065G0603104 12 CER2 0603 X7R 16V 100N P 2513 065G0603104 12 CER2 0603 X7R 16V 100N P 2511 065G0603104 12
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 2218 065G0603330 31 CER1 0603 NP0 50V 33P PM 2451 065G0603479 31 CHIP 0603 4.7PF 50V 2450 065G0603479 31 CHIP 0603 4.7PF 50V 2514 065G0603683 12 CHIP 0603 68NF K 16V X7R 2502 065G0805104 22 0.1UF +-10% 25V X7R 080 2501 065G0805104 22 0.1UF +-10% 25V X7R 080 2517 065G0805223 32 CHIP 0.
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 2419 067G411F1003XT CAP S105℃ 10UF M 16V 2402 067G411F1003XT CAP S105℃ 10UF M 16V 2402 067G411F1003XT CAP S105℃ 10UF M 16V 2503 067G411F4704XT CAP 105℃ 47UF M 25V 2503 067G411F4704XT CAP 105℃ 47UF M 25V 2506 067G411F4704XT
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 5604 071L 56121 TA 0805 120 OHM 3A 6220 093G 60 1P BAT54LT1 SOT-23 6223 093G 60 1P BAT54LT1 SOT-23 6220 093G 60229 BAT54(L4P) 6223 093G 60229 BAT54(L4P) 6202 093G 64 33 DIO SIG SM BAV99 (PHSE)R 6201 093G 64 33 DI
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 1 715G1854 1 MAIN BOARD PCB Q85G 583615 GASKET_ALUMINIUM FOIL Q85G 583619 GASKET_ALUMINIUM FOIL KEPC780HP1P KEY BOARD 1931 033G3802 7 WAFER EH 7 3935 061G0603103 RST CHIPR 10 KOHM +-5% 1/10W 3934 061G0603472 RST CHIPR 4.
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.
