iMac 2.4GHz Intel Core Duo 2007, WHITE SCREEN ON BOOT!!!

Discussion in 'iMac' started by nicholaswade82, Feb 1, 2015.

  1. nicholaswade82 macrumors newbie

    Joined:
    Jan 25, 2009
    #1
    Hello guys, apologies if anyone has opened a thread similar to this. I know its a common-ish problem but I haven't got a clear answer from the forums.

    Basically, I bought an iMac today off eBay 'spares or repair'. Knowingly, it has a white screen on boot problem. I though to myself, I know abit about Macs ie resetting PRAM, SMC, boot keys to force boot from USB, DVD etc. However nothing I have tried is working. This is what I have experienced so far...


    * Turn iMac on, chord chimes once. Computer enters white screen but with NO APPLE LOGO, and NO CURSER. It looks as if its about to boot up. But nothing, it doesn't get past this stage. As I write this, my screen has been white for the past 30 minutes no change.


    *I can hear a fan kicking in, or it maybe the hard drive...im not sure. However certainly no clicks, grinding, whirring sounds.


    *Reset PRAM holding alt, apple, P, R. It goes through the chimes x 3. When buttons are released, it again stalls at white screen.


    *Reset SMC, unplugged all peripherals and power overnight. Held down power for 10-20 seconds. No change.


    *Have removed RAM, turned on computer and I get loud electronic beeps indicating the logic board recognises no RAM. Could be a good sign the logic board has signs of life? Also tried swapping RAM sticks around, no change.


    *Tried booting form DVD, holding CMD C, also CMD D...nothing works. However the keyboard definitely works because I can eject the disc. So the computer is showing signs of life, just no display.


    *Tried booting from USB stick with OSX Lion pre installed, holding down OPTION did nothing.


    *The previous owner told me he replaced the graphics card with a known good one. So it kind of rules that out, but this doesn't look like a graphics problem to me. But I'm no expert!



    I read somewhere on another forum that the hard drive can fail in such a way, that you cannot boot from another device. So if it fails, your only option is to unplug the hard drive so it forces the computer to look elsewhere. Not sure if this is true, but I'm willing to try anything! So I've just ordered some cheap torx drives and suction cups to remove the screen and have a look into the hard drive. I was going to replace the standard HD with an SSD anyway so I am hoping this is the culprit.

    In my head, its calling out hard drive or logic board. Am I wrong? I was going to replace this anyway so I may as well rip open the machine and stick a known working one in. Failing this, should I get a reconditioned Logic Board and try that? Ive looked at some guides and it doesn't look at all hard to replace, just need to be careful.

    PLEASE, if anybody can help point me in the right direction I would be eternally grateful! Many thanks in advance.


    P.S - For your information, I also have a 2008 white MacBook, and a WIndows 8.1 PC I can use for test / diagnostic purposes if anyone knows how, or has any ideas?



    Regards



    Nick
     
  2. dyt1983, Feb 2, 2015
    Last edited: Jun 1, 2015

    dyt1983 macrumors 65816

    Joined:
    May 6, 2014
    Location:
    USA USA USA
    #2
    edit: To remove personally identifying info not relevant to the conversation.
     

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