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Processor upgrade, followed by downgrade freezes system

Hi. I'll try to explain this as best I can, but I'll attempt to be brief. I was running a G4 Sawtooth I bought on e-bay a few years ago with a dual 500 processor (I know AGP machines didn't come with duals, so it had to be an upgraded processor from a later machine—and trust me, this IS an AGP machine. Every known means of identifying the machine confirms this. So, upon Leopard's arrival, I installed a 1.5GHz OWC Mercury extreme. I had to upgrade the firmware before the swap, but all went well. But, since the AGP machines only have a 2x AGP slot and I wanted full benefit of a new video card upgrade (which is in the mail right now) I got a great deal on a Digital Audio machine and pulled the 1.5 processor from the AGP & put it in the DA. Had to change one dip switch for the 133MHz bus, but it worked great in that machine as well. So I decided to put the old dual 500 back in the AGP to use as a wireless station in another room. So what is happening now is that the AGP boots, but within a minute or less, it freezes. Light goes out on the mouse and that's it. I've been looking at resetting PRAM, or possibly the GPU(?) button on the motherboard, but I really don't want to cause any more harm than good by rushing in blindly. Anyone have a systematic list of the procedure's they'd try to troubleshoot and solve the freezing issue after returning the old processor back into the machine it which it originally resided, and worked flawlessly before?

G4 AGP, Mac OS X (10.4.11), 512 MB RAM

Posted on Nov 30, 2007 9:15 PM

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Posted on Nov 30, 2007 11:44 PM

Hi! I assume that you applied thermal paste to the heatsink? Next I would reset the pmu by pressing the button once with all external cables unhooked including the a/c and monitor. Then I would reset the pram. Tom

Sawtooth MB-pmu location
[IMG] http://img96.imageshack.us/img96/5706/sawtoothlogicbd2yu.jpg[/IMG]

PRAM reset
http://docs.info.apple.com/article.html?artnum=2238
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Question marked as Best reply

Nov 30, 2007 11:44 PM in response to garygg

Hi! I assume that you applied thermal paste to the heatsink? Next I would reset the pmu by pressing the button once with all external cables unhooked including the a/c and monitor. Then I would reset the pram. Tom

Sawtooth MB-pmu location
[IMG] http://img96.imageshack.us/img96/5706/sawtoothlogicbd2yu.jpg[/IMG]

PRAM reset
http://docs.info.apple.com/article.html?artnum=2238

Dec 1, 2007 7:53 AM in response to Thomas Bryant

OK. Just to make sure I do this correctly, do I remove the battery before I reset the PMU—(GMU! Well, I was kind of close)—and the power cord is supposed to be unplugged as well, right? I did this one time on an iMac a long time ago and I remember there being a right way and a wrong way to do it. I just can't remember which is which. And I didn't even think about thermal paste since my new processor didn't require it (I'm applying that before I do anything else if I can find a place locally that sells it).

Processor upgrade, followed by downgrade freezes system

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