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Display Dim In HP L1955 19″ LCD Monitor

By on April 9, 2008

The complaint for this HP L1955 model HSTND-2B01 19″ LCD Monitor was dim display. After opened up the cover i saw some burnt mark at the inverter board. Further checking found 3 of the 4 C5707 push pull transistors shorted and front side puntured with a hole! No only that,  both the p-channel FET D10PF06 also shorted and have some burnt mark in it too. The inverter fuse already open circuited!

Since i do not have the original of the D10PF06 I used an equivalent part number to test it out. I switched “On” the display and it shutdown after 1 to 2 seconds! I thought it could be the backlight problem didn’t realized that it was the substitution part number that gave problem. I used  a 15″ LCD Monitor to test out the 19″ backlights (4 backlights) and proven all of the backights were working fine.

hp lcd monitor

The stock that i have FQU11P06 already used up and can’t test the set. I ordered it yesterday and got it today. I took out the replacement number and put in the FQU11P06  PCHANNEL FET, the set came back to life! I have tested it for a while and was not hot to touch. I will run the full test again under Windows high resolution-hope everything is okay.

Conclusion-a wrong replacement of the p-channel FET may lead you think that it was the backlights or inverter IC fault. If possible get the original part number.



  1. Jose E. Kunhardt

    September 11, 2009 at 8:41 am

    I am working on the same monitor but i have no idea how to identify if the c5707 push pull transistors are burnt, i dont see any bulging on the transistors. i should clarify that i dont get a dim display on this unit but a black screnn with a resposive power button and power switch.

  2. admin

    September 11, 2009 at 9:32 pm

    HI Jose,

    You need to remove the transistor and test it with meter.


  3. Kazi Baki

    March 31, 2010 at 4:01 am

    Dear Jestine,
    I have Philips 17 inch LCD, model 107s, allways show popup, attention
    monitor control system locked, this model is common problem,pls say some thing about this

  4. admin

    March 31, 2010 at 9:12 am

    HI Kazi,

    I guess you may have to reprogram the EEprom IC.


  5. Williams Adebowale

    September 7, 2010 at 6:36 am

    I am working on this same Monitor, but can't display on the screen

  6. admin

    September 7, 2010 at 6:54 am

    HI William,

    Is all the output voltages good from the power supply? Does the inverter ic have any supply voltage?


  7. Hassan

    August 12, 2012 at 11:57 am

    Dear Jestine,

    I have hp Lcd model L1955 and problem is that i have found some noise from chopper transformer which result that i hear same sound from my pc speaker.Kindly give me the solutions.


    • Jestine Yong

      August 14, 2012 at 1:19 am

      Hi Hassan,

      Noise usually comes from inductor or transformer. Try open up the monitor and gently know the inductor/transformer with the handle of the screw drive to see if the sound will go away or not.



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