HELP!! mac pro 2008 no display signal, new video card

Discussion in 'Mac Basics and Help' started by lalocura77, Aug 24, 2014.

  1. lalocura77 macrumors newbie

    Aug 24, 2014
    hi everyone, this is the history, i have a 2008 mac pro, with NVIDIA GeForce 8800 GT video card, i did the "oven fix" trick a lot of times on this card, until it stopped working and i had this grey freeze display with the apple logo,
    i thought well i need to get a new video card,and i bought the "Tech ATI Radeon HD4870 512MB GDDR5 PCI Express x16 Dual DVI HDTV" used in working condition,
    i tried this new card and there is no signal at all,not even the freeze screen.
    then i took this new one card and tried on other mac pro and it works, i took my friend's video card from his MAC and put it in my mac, and it does not work,
    the question is: do i need a driver to my new card?
    or the video card was not the issue from the beginning?
    what's the next step if a got a working video card but there still no signal in my display?
  2. n0cus macrumors 6502

    Jul 16, 2012
    It sounds like your PCI slot might be having some issues. Try cleaning it with some compressed air or something. I don't think it is a driver problem.
  3. lalocura77 thread starter macrumors newbie

    Aug 24, 2014

    thanks for you answer n0cus, i did it, but nothing happend, the old video card shows the freeze screeen with the apple logo, and the new card "no signal"
    i can hear the chime , the fan, then after a few minutes the mac chime again like its triying to boot,
  4. n0cus macrumors 6502

    Jul 16, 2012
    You might want to try resetting the PRAM. Hold the Option-Command-P-R keys while the computer is starting up. The computer will likely keep on restarting until you let go of the keys. Keep holding the keys until you hear the chime for a third time. Try this with both the new and old graphics cards. If that doesn't work, try booting into safe mode by holding the shift key while booting up. Try these and report back. We are going to solve this problem! ;)
  5. lalocura77 thread starter macrumors newbie

    Aug 24, 2014

    hi n0cus, i have tried all that tricks this last days..the issue is in the hd, now im triying to do a fresh install of MAC os x snow leopard,with the dvd install i got from some torrents, but i couldn't, i have tried formatting,, erase..partition and a lot of stuff i read in online forums a, and nothing super tired with this issue now , tomorrow im going to buy a original dvd installer from the apple store $20, because i dont know why is not working , i have tried a lot of ways. I'll let you know whats the result after that, thanks!!


    by the way i forgot , the old video card it was not broken, i removed the HD, from my mac , and using some sata conectors and some software from the internet, i could read the mac hd in my PC, and i notice the MAC HD has only 20GB, after i removed and back up a lot of stuff, i placed the HD with more than 100gb of free space back in the MAC, and the old video card worked again, but the mac its not booting ,lke i said next step , get the original dvd installer.. let's see
  6. n0cus macrumors 6502

    Jul 16, 2012
    Yeah, that should hopefully work. Don't use OS X torrents, they usually have some issues and are also illegal. I wish you luck my friend. Keep me informed.
  7. lalocura77 thread starter macrumors newbie

    Aug 24, 2014
    THANKS! I will
  8. Bombasstic macrumors newbie


    Mar 4, 2016
    Did you ever resolve this? what was it... i have the same issue, old card worked, apple logo,
    would not get past the apple screen, new video card, no sugnal , then the old video card stopped
    working also.... chime, fans then continues booting but no signal on monitor?

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7 August 24, 2014