Need help with a Powerbook G4 15" 1.25ghz

Discussion in 'PowerPC Macs' started by Jbarnes1111, Mar 29, 2008.

  1. Jbarnes1111 macrumors newbie

    Mar 29, 2008
    Ok, about 3 weeks ago I replaced the DC in board on my wife's 15" G4 1.25 powerbook. When I replaced the logic board I cleaned off all the heat paste and reapplied new generic while silicone based heat paste from Radio Shack in exactly the same places and quantities as the factory did. I did not know about Arctic 5 at the time. The computer has worked fine ever since until earlier this week.

    It had been on running for a while when my wife noticed a "hissing" noise coming from the computer. She said she could smell a hot, burning smell and the computer was frozen with Safari up. She shut it down, and later tried to reboot it with no luck. When you power it up the grey screen comes up and the spinning clock comes up, but it does nothing, and after a while it goes to a blue screen.

    I just removed the logic board again, and am wondering what has failed. There was good coverage of thermal paste on all the spots that Apple used it. The paste on the processor area was wet around the edges - almost like the paste had sizzled the moisture out of itself?

    So, what does this sound like to you? Would the white paste versus arctic silver cause a meltdown? How can I test the processor?

    Oh - and if you think it's the paste I need to know fast. My mother in law's G4 got the same paste at the same time when I went in and resoldered the dc in jack back into the dc in board that it had broken loose from. I told her not to use it till I figure out what happened!

    I have seen people posting screenshots showing the cpu temp - how do you monitor that??

    Thank you!
  2. PowerBookRelic macrumors 6502

    Mar 7, 2008
    I have no idea about the heat paste, but as far as monitoring your system's temperature, many people use the iSTAT is a link:
  3. NIPRING macrumors 6502

    Jan 19, 2008
    Waukesha WI
    Does the radio shack paste have a max temp rating? Maybe it isnt rated that high? I'm just speculating.
  4. The Flashing Fi macrumors 6502a

    Sep 23, 2007
    Sounds like you used too much. You shouldn't have any oozing from the sides. When it comes to Thermal grease/paste, more isn't better and can often cause overheating (I've read that the MBPs have too much paste/grease).

    Here are arctic silver's instructions on properly applying thermal paste:

    I know it's arctic silver's, but it should be the same for any brand.

    Hopefully this helps.
  5. Jbarnes1111 thread starter macrumors newbie

    Mar 29, 2008
    Well, it turned out to be a dead hard drive rather than a logic board problem. I had jumped to that conclusion due to the coincidence of just having the logic board out for the first time ever. I also was mislead by the lack of the start-up chime thinking that signified a problem.

    Now, if I just knew a good way to retrieve data from the dead drive! The disk utility on the Tiger install disk says the drive statuts is failed, and will not aloow and repairs or verification. Any suggestions on this one?

    Thank you,
  6. maxshanly macrumors member

    Jun 12, 2007
    This is going to sound stupid, but put it in the freezer (in a freezer bag) for half an hour and then try it.

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