ThinkPad T40 black screen

Discussion in 'PC Hardware' started by catdog215, Jan 12, 2011.

  1. catdog215

    catdog215 MDL Senior Member

    Oct 21, 2009
    396
    20
    10
    #1 catdog215, Jan 12, 2011
    Last edited: Jan 12, 2011
    hope some1 can help guide me. i had a ThinkPad T40. recently every time i turn on the screen when black. i power off and heard a one long and 2 short beep. I check the beep code and it said "Video (Mono/CGA Display Circuitry) issue."
    Anyway i can fix this problem? one more is that if it POST and if i don't touch anything, it makes to the desktop. on the desktop, it i touch keypad or even slide the laptop an inch it will cause black screen. could it be LCD?

    could it be the motherboard and lcd is dying out?
     
  2. 2centsworth

    2centsworth MDL Senior Member

    Feb 12, 2008
    333
    24
    10
    #2 2centsworth, Jan 13, 2011
    Last edited: Jan 13, 2011
    Try an external monitor, if you still have the same issue it's likley the internal hardware (video card) and possibly a loose or broken connection from what you describe. The BIOS beeps indicate the video system could not be initialized which points to a video card or hardware problem. A broken video cable would not cause BIOS beeps.

    Also check the DIMM's are seated, if needed remove battery then carefully remove and re-insert the DIMM's. One last small chance other thing to try is removing the wifi mini PCI card and see if the problem goes away.
     
  3. WindDrake

    WindDrake MDL Novice

    Jun 2, 2008
    25
    1
    0
    IBM T4x and R5x boards both share the same failure you're describing. It's caused by the GPU (Radeon 7500, X300, 9000, FireGL) BGA's failing due to thermal cycling and the unfortunate location of the BGA in relation to how the case stresses.

    You'll need a Reflow of the GPU BGA.
     
  4. 2centsworth

    2centsworth MDL Senior Member

    Feb 12, 2008
    333
    24
    10
    The Ball Grid Array low temp solder defects affect a number of vendors boards with high temp VGA chips from both AMD/ATI and Nvidia. Excessive high temps then cooling cycles break the solder joints......as for reflowing it himself...if you're experienced with soldering and maybe have a temp controlled heat gun...but not something most people can do themselves.

    If you believe that to be your problem after basic steps above, then you might want to research the proper temp to use trying to get the solder melted again without damaging other components on the board. The same problem will re-occur unless you cool the GPU better....just 2 cents worth today.
     
  5. catdog215

    catdog215 MDL Senior Member

    Oct 21, 2009
    396
    20
    10
  6. catdog215

    catdog215 MDL Senior Member

    Oct 21, 2009
    396
    20
    10
    Is that true that the Reflow GPU fix guide is heating the old ATI chip? I guess all i need to buy is an infrared thermometer and a heat gun @ homeDepot or Lowes. Buy it and return for a refund :)
     
  7. 2centsworth

    2centsworth MDL Senior Member

    Feb 12, 2008
    333
    24
    10
    Yes. The steps outlines in your link look accurate, then temp I am unsure of. You want to get it hot enough to just melt the solder balls but not any hotter, then let it cool not too quickly initally. Be certain to pay close attention to the other components nearby it and sheild them, so that you don't overheat any of them. Good luck and if it works please post what you did for others to refer to.

    You might be able to apply additional pressure to the VGA chip pressing it into the PCB instead of soldering it, but reflow is the only real solution if that is indeed your problem. Once repaired you prolly need to cool the VGA chip better to prevent a repeat over time. Reapply quality thermal compound to the heatpipe that the VGA uses, be certain it's tightened down and consider a software utility or BIOS update (they usually lower the operating frequency) if available to keep the VGA running cooler. You can use third party utilities to lower the clock speed of the VGA chip.