iMac 20in aluminum (late 2007) LED diagnostic questions

Discussion in 'iMac' started by qwerty143, Aug 18, 2010.

  1. qwerty143 macrumors newbie

    Joined:
    Aug 18, 2010
    #1
    I recently bought an used iMac (was purchased new in feburary 2009) in which I knew the screen was not showing any video when I bought it. ( I was okay with that I thought I'd give it a go at fixing) well the problem seems to be within the LCD itself. When I hit the power button I hear the chime, fan spins, and the hard drive does it's thing. I ended up taking the casing off the iMac to where it only shows the bottom half of the insides underneath the LCD. My question is now to diagnose what exactly is wrong with it by using the 4 led lights. I have searched the forums and the Internet up and down for which ones mean what but I have only found out information on older iMacs. When my iMac is off (still plugged in) LED 1 is on. When I turn the iMac on LED 1,2, and 3 are green. Which that leaves the 4th LED not being lit up at all. I suspect this has something to do with the iMac not showing any video but as I said I am not sure because I cannot find any information on it anywhere. Any information would so helpful and I thank all you for your time.
     
  2. AlphaDogg macrumors 68040

    AlphaDogg

    Joined:
    May 20, 2010
    Location:
    Boulder, CO
    #2
    If you have an external display and adapter, plug it in to the imac. If an image shows up on the external display, it could either be the logic board or lcd. If an image doesnt show up on the external display, it could be the video card (new logic board).
     
  3. qwerty143 thread starter macrumors newbie

    Joined:
    Aug 18, 2010
    #3
    I am getting no video via dvi to hdmi on my television screen. Does anyone have any information concerning the LEDs behind the sata cable? Like i said before the first 3 come on but the fourth does not. Anyone know anything about it? thanks again for your time.
     
  4. AlphaDogg macrumors 68040

    AlphaDogg

    Joined:
    May 20, 2010
    Location:
    Boulder, CO
    #4
    I'm sorry, but this likely means you need a new logic board. Take it to the apple store and see if they can do some troubleshooting...
     
  5. qwerty143 thread starter macrumors newbie

    Joined:
    Aug 18, 2010
    #5
    ughh the nearest apple store is 4 hours away. We do have an certified apple reseller but last time i used them they broke off a screw in my imac so i dont trust them at all.
     

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