6 Replies Latest reply: Sep 28, 2006 12:37 AM by mrtotes
drewwid Level 1 Level 1 (0 points)
Someone gave me an imac flat panel (800/15 inch) and it won't power on. I hit the power button and the fan spins up but that is all. No chime, don't hear the hard drive spin up, and no video. I have reset the pmu and let it sit overnight with cmos battery out and still nothing. Am i to assume the logic board is toast or is there something else i should try?

imac 800 15inch, Other OS
  • 1. Re: imac won't power on.  any suggestions?
    mrtotes Level 6 Level 6 (11,815 points)
    Many iMac G4 suffer from black-displays but then that doesn't explain the loss of Start-Up chime.

     

    The only thing I'd say is check the RAM is all seated correctly and that all the connections on the logic-board are firm.

     

    If you've got the MiniVGA to VGA adaptor you could try hooking it up to an external display.

     

    Does the Caps-Lock lamp show?

     

    Zap the PRAM?

     

    My feeling is that you were given it because it's dead. An 800MHz iMac isn't worth fixing up - their logic boards don't have USB2, Airport Extreme, Video-Out or Audio-in and cost about 80% of a new Intel Mac Mini.

     

    regards

     

    mrtotes

  • 2. Re: imac won't power on.  any suggestions?
    drewwid Level 1 Level 1 (0 points)
    Well i disected the machine and made sure every connection is tight. Reseated the memory but still nothing. Won't even start from the keyboard. Besides hitting the pmu reset and removing the battery overnight is there another way to zap the pram? These are selling for 500 ish working on ebay so i am tempted to buy a board there for around 150 to see if i can get it going.
  • 3. Re: imac won't power on.  any suggestions?
    mhunter Level 6 Level 6 (9,190 points)
    Have you tried installing a new battery?

    Sometimes a dead PRAM battery (what you are calling a CMOS battery) is enough to keep a Mac from starting-up.


    I hope this helps.

    Let us know if you have other questions.


    P.S., if you'd like, go ahead and click the "Helpful" or "Solved" buttons on any of the posts / replies above if you feel they were helpful or adequately answered your question.
  • 4. Re: imac won't power on.  any suggestions?
    drewwid Level 1 Level 1 (0 points)
    Yep. What was strange was when i received it the battery was missing (very suspect) so i did go and buy a new one.
  • 5. Re: imac won't power on.  any suggestions?
    mhunter Level 6 Level 6 (9,190 points)
    O.K., it was worth checking

    I do suspect that the other poster is correct; you were likely given the machine because they knew it had a problem.

    As you suggested, you may consider getting a replacement logic-board. And, that may fix it. But, it may also just be the power supply (if it is not providing the exact voltage it should, then it could cause these problems).

    So, you could go about changing parts around, and end-up completing an entire circle and have more into the machine than it is worth. Of course, the learning experience may be worth it to you.

    I hope this helps.

    Let us know if you have other questions.


    P.S., if you'd like, go ahead and click the "Helpful" or "Solved" buttons on any of the posts / replies above if you feel they were helpful or adequately answered your question.
  • 6. Re: imac won't power on.  any suggestions?
    mrtotes Level 6 Level 6 (11,815 points)
    Changing the logic board is difficult. (By comparison changing the optical drive/hard drive is easy.)

    If you do get one it must be a 800MHz/700MHz board - the 1GHz & 1.25GHz boards are a different design and won't fit.

     

    I'm with mhunter though unless you want the learning experience. iMacs with dual-core Intel processors and 17" LCDs start at $999 (less if you go refurbished - today there is a $949 one there).

     

    regards

     

    mrtotes