Mac Mini G4 unstable

[eric]

I took a chance on a vague Mini G4 auction the other day and am trying to get it to run.. well anything.. but constant crashes abound.

It turned out to be just the base 1.25ghz model, no wifi, 256mb ram.

First the HDD sounded terrible and there was a MacBook restore CD in it. Replaced the HDD and started installing 10.4. On CD 2 it kept halting and having weird artifacts on screen. I thought maybe the CD drive was dead too, so I used an external USB CD drive to finish the install. Once the Mini starts it crashes almost instantly.

I thought maybe the RAM - ran Apple Hardware test 5 times, no errors. Replaced the DIMM with a 512mb. I was able to install completely this time but still get crashes after a minute or two.

There's not much left to replace or test (that i know of) - new ram, new hdd (also tested another hdd from a laptop, same results), different cd drive.

Any pointers on what to look at next?

 

[eric]

The cooling on this thing is odd - the GPU is just pressed onto a thermal pad to the bottom of the case, which is what dissipates heat. I held a fan over it and was able to run it at 80c (vs 105c bare) and got no artifacts for ~10 min - though after 10 mins I started seeing them again.

Many older forum posts about heat and the G4 are just people saying "Intel is hotter, dont worry about G4 temps" which - maybe at the time was true, but now they're vintage and things change.

I think I'll take the CPU heat sync off and clean and re-apply thermal compound as well as get a new thermal pad that will make better contact. Worst comes to worst I'm considering cutting a hole in the bottom and attaching a short heat sync or fan!

 

[Stephen]

The cooling on this thing is odd - the GPU is just pressed onto a thermal pad to the bottom of the case, which is what dissipates heat. I held a fan over it and was able to run it at 80c (vs 105c bare) and got no artifacts for ~10 min - though after 10 mins I started seeing them again.

Many older forum posts about heat and the G4 are just people saying "Intel is hotter, dont worry about G4 temps" which - maybe at the time was true, but now they're vintage and things change.

I think I'll take the CPU heat sync off and clean and re-apply thermal compound as well as get a new thermal pad that will make better contact. Worst comes to worst I'm considering cutting a hole in the bottom and attaching a short heat sync or fan!

If it's an endeavor you're willing to undertake... a copper shim with thermal paste will be significantly more performant than a heat pad.

 

[Towmater]

Possibly the o.o. did the simple mod to speed it up? I think it involved removing a surface mount resistor.