Red diagnostic lcds on Mac ATI Radeon X1900XT

Discussion in 'Mac Pro' started by Graemezee, Oct 14, 2009.

  1. Graemezee macrumors newbie

    Oct 14, 2009
    My ATI Radeon X1900XT graphics card keep tripping out leaving a black screen
    The card itself has a red lcd light visible on the card when the screen is not working

    The card is in an 8 core mac pro and is running a 30" ACD.
    It started a while a go before installed Snow Leopard but happened very infrequently

    Have installed snow leopard and added two new dvd drives and I now have these blackout nearly everyday.

    Have found info on ATI's website about the Radion HD 4870 suggesting the LCDs indicate a faulty power supply or even disconnected power leads
    the same thread also mentioned overheating could be the cause a of the red light.

    anyone know what the Red diagnostic lcds on Mac ATI Radeon X1900XT mean.

    Extra info: The two DVDs I have added I had to replace the data cable as I damaged the original
    to do this meant a total strip down, while I was there I added two sata data cable threading them through connecting to a new sata drive and leaving one spare for the future.

    The DVDs work perfectly, could adding the sata cables have an effect on the power supply.
    Having to remove the ATI Radeon X1900XT, I am sure the cables are seated correctly, should it matter which cable is connected to each connector on the motherboard.

    There is a thread on apple website about this black screen, all describing similar problems but relating this to Snow Leopard and some sort of video bug.
    No answers on that site and no one else seem to have the Red diagnostic lcd's

    Thanks in advance Graeme
  2. Cindori macrumors 68040


    Jan 17, 2008
    x1900 is known to clog up with dust , or just fail generally

    try blow out any dust, otherwise probably heating has damaged some components anyway. you should start looking for replacement (3870, 4870)
  3. roglowe macrumors newbie

    Jun 3, 2011
    ATI Radeon X1900 XT Red Light and Fan Fail fixed.

    I thought I would share this.
    My mac pro HD 30" screen went blank. I powered off and on. Still no joy.
    I opened the tower and saw a red light and the card was hot as coles.:eek:

    "I had this card out a few weeks back to blow the dust off to stop the fan being noisy. Worked a treat.":D

    I put a 9v battery to the fan and checked it. All ok. Then I looked at the wiring for the fan. It appeared lose on the board from the little wight connector. And it was. I pushed it back into place and all works ok now. I must have losened it when I cleaned it a few weeks ago. :eek:

    So just a thought for anyone that has a red light and the fan stops. Check if the connector is lose especially if you had the card out recently to clean it. :D


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