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HP L1940T Service Manual
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HP L1940T Service Manual

Hp l1940t lcd monitor
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19" LCD Color Monitor
HP L1940T

SERVICE MANUAL

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.
1

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Summary of Contents for HP L1940T

  • Page 1: Service Manual

    19" LCD Color Monitor HP L1940T SERVICE MANUAL 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,...

  • Page 2: Table Of Contents

    19" LCD Color Monitor HP L1940T 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.

  • Page 3: Revision List

    19" LCD Color Monitor HP L1940T Revision List Revision Date Revision History TPV Model Sep.-08-06 Initial release T981KMNDKHHPQP T981KGNDBHHPQP T96HNNDBC6HPQP T981KMNDBHHPQP T96HNNDKC6HPQP Nov.-15-06 Add new BOM T96GNNDKC6HFQP T96GNNDMC6HFQ T96GNNDMC6HPQP T96HNNDBC6HFQP T96HNNDMC6HFQ...

  • Page 4: Monitor Specification

    19" LCD Color Monitor 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 0.294mm(H) x 0.294mm(V) LCD Panel Viewing Angles (TYP) H: 150; V: 130 Response time (typ.) 8 ms...

  • Page 5: Lcd Monitor Description

    19" LCD Color Monitor 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: Operation Instructions

    19" LCD Color Monitor HP L1940T 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.

  • Page 7: Adjust The Picture

    19" LCD Color Monitor HP L1940T 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”...
  • Page 8 19" LCD Color Monitor 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...

  • Page 9: Input/Output Specification

    19" LCD Color Monitor HP L1940T 4. Input/Output Specification 4.1 Input Signal Connector Analog Connector Pin layout 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...
  • Page 10 19" LCD Color Monitor 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...

  • Page 11: Factory Preset Display Modes

    19" LCD Color Monitor 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...

  • Page 12: Panel Specification

    19" LCD Color Monitor 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...

  • Page 13: Optical Characteristics

    19" LCD Color Monitor HP L1940T 5.2 Optical Characteristics Test Conditions Optical Specifications...

  • Page 14: Monitor Exploded View

    19" LCD Color Monitor HP L1940T 6. Monitor Exploded View...

  • Page 15: Block Diagram

    19" LCD Color Monitor HP L1940T 7. Block Diagram 7.1 Scalar Board LCD Interface (CN501) Scalar IC NT68663MEFG-128 (Include ADC, OSD, MCU) (U401) H sync V sync EEPROM Key Board M24C16-WBN6 Control (U302) D-Sub (CN402) Crystal Connector 12MHz (CN201) (Y301)
  • Page 16 19" LCD Color Monitor HP L1940T 7.2 Inverter / Power Board Bridge Diode Transformer Rectifier Rectifier&filter EMI filter and Filter Start Circuit R904/R910 CON951 Over Control IC Voltage Protect ON/OFF resonance Lamp Full bridge Start Feedback OZ9938GN switch circuit circuit...

  • Page 17: Maintainability

    19" LCD Color Monitor HP L1940T 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.
  • Page 18 19" LCD Color Monitor HP L1940T 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 Measure CN401 PIN7/8=12V? PIN10/11=3.3V?
  • Page 19 19" LCD Color Monitor HP L1940T No picture (LED is orange) No picture Key is under control? 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...
  • Page 20 19" LCD Color Monitor HP L1940T Panel Power Circuit Measure Q403 base is high level? Y301 oscillate waveforms are normal Check Q403 and Q402 are broken Replace Y301 or CN301 solder? Replace U401 Check Correspondent component. Replace U403 Replace PANEL...
  • Page 21 19" LCD Color Monitor HP L1940T 8.2 Power Board 1. No Power No power Check AC line volt 110V or 220V Check AC line Check the voltage of C907(+) Check F901, bridge rectified circuit Check start voltage for the pin8 of IC901...
  • Page 22 19" LCD Color Monitor HP L1940T 2. W/LED No Backlight Measure C811 (+) =12V Disconnect Q821/Q841 with IC Check power board part ,check C811 (+) =12V? Check Q873 or Check ON/OFF signal Q874 Check main board ON/OFF circuit Check PT801/PT802...
  • Page 23 19" LCD Color Monitor HP L1940T 3. Protected 1 Striking function debug Connector CTIMER to GND and turn on power supply OVP normally Check OVP circuit End Striking function debug 4. Protected 2 FB and protection loop debug Connector CSST and REF and turn on power supply...

  • Page 24: Schematic

    HP L1940T 9. Schematic 9.1 Main Board R202 　 1/16W DVI-SCL DVI_5V R203 　 1/16W DVI-SDA CN202 DDC-DVI-SCL DVI-D-Female FB202 C202 ZD202 ZD203 UDZS5.6B UDZS5.6B SHELL1 120 OHM 0.1uF DDC-DVI-SDA D203 BAV70 AGND A VS TX2- RX2- RX2+ TX2+ DVI_5V...
  • Page 25 HP L1940T CN302 FB302 TXO0- TXO0+ +3.3V ADC_VAA TXO0- TXO1- 120 OHM TXO0+ TXO1+ TXO1- TXO2- IICSCL TXO1+ TXO2+ C302 C303 C304 TXO2- 10uF/16V 0.1uF 0.1uF IICSDA TXO2+ TXOC- TXOC- TXOC+ RSTN TXOC+ TXO3- TXO3- TXO3+ IRQN TXO3+ TXE0- FB303...
  • Page 26 HP L1940T...
  • Page 27 HP L1940T FB402 CUT_A +12V USB_+5V L401 CUT_A BRIGHTNESS 120 OHM R402 R403 BRIGHTNESS (3) C402 　 1/16W 　 1/16W 35uH 0.1uF R404 R405 BL_CONTROL R406 C404 BL_CONTROL (3) 　 1/16W 　 1/16W C403 　 1/16W CN401 10uF/50V PANEL_IDX R407...
  • Page 28 HP L1940T +3.3V +3.3V USB3V3 R524 R501 10K　 U502 Q502 AT25040AN-10SU-2.7 R503 SI5441DC SPICS R502 　 1/16W C523 　 1/16W 0.1uF SPISD R504 　 1/16W R505 15K 　 1/16W GND_U HOLD 100K 　 1/16W GND_U R506 15K 　 1/16W R507 　...

  • Page 29: Inverter/Power Board

    HP L1940T 9.2 Power Board (include inverter and power) Inverter Schematic Philips HPL1940T/L1740 PCB : 715G1821-1/715G1995-1 PT801 C802 CN831 5pF/3KV R834 CONN +12VCC 6.2M 　 1/2W_NC C803 C801 5pF/3KV R835 10pF/6KV R831 C820 C821 R822 R823 1K　 10K_1% 470uF/25V R824 C838 7.5K_1%_NC...
  • Page 30 HP L1940T Adapter Schematic Philips HPL1940/L1740 PCB : 715G1821-1/715G1995-1 L902 S901 R931 C8B-R6H_NC spotgap_NC 2R2_1206 R900 C900 C931 R932 680K 0.001uF/250V 2R2_1206 3.3nF/500V T901 L901 R901 C908 +12V VAR901 680K 0.47uF/275V CN901 varistor_NC C901 AC SOCKET R904 R905 C920 D931 0.001uF/250V...

  • Page 31: Pcb Layout

    19" LCD Color Monitor HP L1940T 10. PCB Layout 10.1 Main Board...

  • Page 32: Inverter/Power Board

    19" LCD Color Monitor HP L1940T 10.2 Inverter / Power Board 10.3 Key Board...

  • Page 33: White-Balance, Luminance Adjustment

    = 313±20, y = 329 ±20, Y= 150 cd/m 3. Into factory mode of HP L1940T 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”...
  • Page 34 19" LCD Color Monitor 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.

  • Page 35: Edid Content

    19" LCD Color Monitor HP L1940T 12. EDID Content Analog 16 : 32 : 48 : 64 : 80 : 96 : 112: Digital 16 : 32 : 48 : 64 : 80 : 96 : 112:...

  • Page 36: Bom List

    19" LCD Color Monitor HP L1940T 13. BOM List T981KMNDKHHPQP 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...
  • Page 37 19" LCD Color Monitor HP L1940T 034G6401AFH B 30 BEZEL 705G980KM34004 MAIN FRAME ASS'Y 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...
  • Page 38 19" LCD Color Monitor HP L1940T 7601 056G 545500 IC USB HUB GL850A 64PIN GENESYS 7401 056G 562 70 GM5321 QFP-208 7403 056G 563 27 IC AIC1117A-18PYTR-R SOT223 7202 056G1133 20 AT24C02N-10SU-2.7 7203 056G1133 20 AT24C02N-10SU-2.7 7202 056G1133 34 M24C02-WMN6TP...
  • Page 39 19" LCD Color Monitor HP L1940T 3401 061G0603101 RST CHIPR 100 OHM +-5% 1/10W 3340 061G0603101 RST CHIPR 100 OHM +-5% 1/10W 3309 061G0603101 RST CHIPR 100 OHM +-5% 1/10W 3308 061G0603101 RST CHIPR 100 OHM +-5% 1/10W 3226 061G0603101...
  • Page 40 19" LCD Color Monitor HP L1940T 3203 061G0603103 RST CHIPR 10 KOHM +-5% 1/10W 3202 061G0603103 RST CHIPR 10 KOHM +-5% 1/10W 3209 061G0603104 RST CHIPR 100 KOHM +-5% 1/10W 3229 061G0603104 RST CHIPR 100 KOHM +-5% 1/10W 3515 061G0603104...
  • Page 41 19" LCD Color Monitor HP L1940T 3520 061G0805180 1F RST CHIPR 1.8 KOHM +-1% 1/8W 3519 061G0805472 RST CHIPR 4.7 KOHM +-5% 1/8W 3521 061G0805560 1F RST CHIPR 5.6 KOHM +-1% 1/8W 3517 061G1206000 RST CHIPR 0 OHM +-5% 1/4W...
  • Page 42 19" LCD Color Monitor HP L1940T 2619 065G0603104 12 CER2 0603 X7R 16V 100N P 2618 065G0603104 12 CER2 0603 X7R 16V 100N P 2615 065G0603104 12 CER2 0603 X7R 16V 100N P 2612 065G0603104 12 CER2 0603 X7R 16V 100N P...
  • Page 43 19" LCD Color Monitor HP L1940T 2412 065G0603104 12 CER2 0603 X7R 16V 100N P 2411 065G0603104 12 CER2 0603 X7R 16V 100N P 2410 065G0603104 12 CER2 0603 X7R 16V 100N P 2409 065G0603104 12 CER2 0603 X7R 16V 100N P...
  • Page 44 19" LCD Color Monitor HP L1940T 2437 067G 312100 3T SMD 10uf +-20% 16V 2437 067G 312100 3T SMD 10uf +-20% 16V 2437 067G 312100 3T SMD 10uf +-20% 16V 2439 067G 312100 3T SMD 10uf +-20% 16V 2616 067G 312100 3T...
  • Page 45 19" LCD Color Monitor HP L1940T 5607 071G 57G800 FT CHIP BEAD TI321611G800 FRONTIER 5606 071G 57G800 FT CHIP BEAD TI321611G800 FRONTIER 5605 071G 57G800 FT CHIP BEAD TI321611G800 FRONTIER 5601 071G 57G800 FT CHIP BEAD TI321611G800 FRONTIER 5503 071G 57G800 FT...
  • Page 46 19" LCD Color Monitor HP L1940T 6204 093G 64 33 DIO SIG SM BAV99 (PHSE)R 6203 093G 64 33 DIO SIG SM BAV99 (PHSE)R 6203 093G 64 33 DIO SIG SM BAV99 (PHSE)R 6203 093G 64 33 DIO SIG SM BAV99 (PHSE)R...
  • Page 47 19" LCD Color Monitor HP L1940T Q40G 45769020B CARTON/PALLET LABEL Q40G19NP690 1E RATING LABEL Q41G160069041C L1940T DOC KIT EUR Q41G7800690A19 RTF CARD Q44G3957690 1F CARTON Q45G 76 28A05 pe bag Q45G 77 5 PE PACKING Q45G 88609 28 BASE P.E BAG Q45G 88609 29 P.E.BAG(EPE)
  • Page 48 POWER CORD 2nd source 705G980KM34005 MAIN FRAME ASS'Y 015G6343 3 MAIN FRAME E750L 750GLH9013A81Z000H PANEL LCD 19" ME13 A16 REV.2 D HP HSD 2nd source E750L 750GLH9013A82Z000H PANEL HSD190ME13 A16 REV.2 NJ HSD CBPC980KHNHPP CONVERSION BOARD G1864-1-X-X-1-070122 C319 065G0603339 31 CAP:CER 3.3PF 50V SMT 0603...
  • Page 49 E089 089G179J30H712 FFC CABLE 705G980KM34005 MAIN FRAME ASS'Y 015G6343 3 MAIN FRAME E750L 750GLH9013A81Z000H PANEL LCD 19" ME13 A16 REV.2 D HP HSD 2nd source E750L 750GLH9013A82Z000H PANEL HSD190ME13 A16 REV.2 NJ HSD CBPC980KHNHPP CONVERSION BOARD G1864-1-X-X-1-070122 C319 065G0603339 31 CAP:CER 3.3PF 50V SMT 0603...
  • Page 50 PANEL LM190E08-TLB2 KR LPL CBPC6GNNHPQ2P CONVERSION BOARD G1864-1-X-X-1-070122 PWPC1942LGH4P POWER BOARD G1821-1-X-X-1-070117 ZD874 093G 39GA01 T RLZ5.6B Q41G160069040C DOCKIT L1940T AP Q85G 583609 GASKET_ALUMINIUM FOIL U401 056G 562117(LHPND09GKQ2) IC NT68663MEFG-128 QFP-128L Diversity of T96GNNDMC6HPQP compared with T981KMNDKHHPQP Location Part No.
  • Page 51 105℃ 2200UF M 10V C932 067G215S1024KV EC 105℃ CAP 1000UF M 25V C956 067G215Y4713NV KY16VB470M-CC3 8*15MM 2nd source C956 067G215Y4713RV LOW E.S.R 470UF +-20% 16V C907 067G215Z10115K ELCAP 100UF M 450V Q41G160069041C L1940T DOC KIT EUR U401 056G 562117(LHPND09HKQ3) IC NT68663MEFG-128 QFP-128L...
  • Page 52 105℃ 2200UF M 10V C932 067G215S1024KV EC 105℃ CAP 1000UF M 25V C956 067G215Y4713NV KY16VB470M-CC3 8*15MM 2nd source C956 067G215Y4713RV LOW E.S.R 470UF +-20% 16V C907 067G215Z10115K ELCAP 100UF M 450V Q41G160069040C DOCKIT L1940T AP U401 056G 562117(LHPND09HKQ3) IC NT68663MEFG-128 QFP-128L...

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