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  1. #1
    Join Date
    Apr 2012
    Posts
    18

    Default Temperamental PowerMac 7500

    I have a PowerMac that is so temperamental tonight, it's not even funny.

    Here's what it's doing.

    First of all, the plastic case has become very brittle inside, that I have to be super careful now, and I had it apart to try and make some repair to the plastics.

    So I get done, put it back together, and no boot. It does the chime, but nothing.. I take it apart, pull all PCI cards, and it boots, but now I'm using the onboard video.

    So here's the specs.
    Sonnet Crescendo G4 1GHz
    1GB RAM (8x 128MB FPM RAM)
    ATI Radeon 9200 128MB PCI
    Sonnet Tempo Ulta 100 PCI
    40GB IDE HD
    DVD-RW IDE Pioneer Drive

    So, with that in mind, PCI cards removed, it booted, but like I said, on the onboard video. So I put just the video card in, no boot. I try then with only the Tempo card, it boots. Fine, it's just a video card then, so I grab my other card that I have out of my G3 mini tower, that still works, same card. No boot then. At that point, I'm confused. What the heck??

    I then try hooking TWO monitors up, one to onboard, one to the ATI.. It boots! And on both screens.. But why is it doing this now? At this point, I try resetting the CUDA and PRAM. With the ATI, PRAM won't reset, but without, it resets. Oookkaaayy.. Anyway, still acts the same.

    At this point, I'm drinking beer and cussing the thing out, and just give up and put the cards back in and hook it up the way it should be hooked up, and literally said "If you don't work your in the trash tomorrow", and what do you know, it BOOTED UP. And not only that, is playing Unreal Tournament without any lockups.

    What in the world was THAT all about? It's never been that hard to boot before?

    Oh, and during all my troubleshooting, I did get a odd mac system error on boot one time, when I had the two monitors attached, the onboard video showed a system error at the top right of the screen, halfway OFF the screen, and it said: "Sorry, a system error occurred: divide by zero"

    Any ideas? I'm afraid to shut the machine down as if it's going to do this again.

  2. #2
    Join Date
    Mar 2001
    Location
    Virginia... where one Democrat CAN make a difference
    Posts
    2,929

    Default

    Remove your onboard video ram blow the dust out of the sockets and firmly reseat the video ram.

    Wouldn't hurt at all to do the same to the system ram.

    When was the last time you changed the motherboard battery?
    Damien,

  3. #3
    Join Date
    Apr 2012
    Posts
    18

    Default

    Quote Originally Posted by Damien View Post
    Remove your onboard video ram blow the dust out of the sockets and firmly reseat the video ram.

    Wouldn't hurt at all to do the same to the system ram.

    When was the last time you changed the motherboard battery?
    I changed the battery about 3 weeks ago.

    I'll try cleaning the RAM and see what happens. I honestly wouldn't even care if there was no video RAM installed, I'd prefer to not use the onboard video at all if possible.

  4. #4
    Join Date
    Apr 2012
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    18

    Default

    I'm beginning to think this may be DVD drive related.

    With the power cord to my DVD burner in, the computer intermittently starts up (but when it does the drive reads fine), when unplugged it always starts up fine. Hmm.

  5. #5
    Join Date
    Mar 2001
    Location
    Virginia... where one Democrat CAN make a difference
    Posts
    2,929

    Default

    If you get it running on the video card you can remove the onboard ram completely and it won't hurt anything.

    Could be the DVD drive, do you have a spare you can swap for a test? Could also be a symptom of a failing power supply. I had that happen once. On a Mac that old you never know, it could be anything.
    Damien,

  6. #6
    Join Date
    Apr 2012
    Posts
    18

    Default

    Only spare DVD drive I have can't read CD-R's...

    I'm noticing a few kinks in the IDE ribbon, it might be time to just replace the drive and ribbon alltogether, and maybe the PSU too.

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