[saxman]

Does anybody know if the small CPU fan screwed onto the heatsink of the 6o3ev chip is supposed to run all the time or does it have a thermo switch?

I took it out to clean it (it was filthy and noisy) and now it appears not to work (whoops!) Mac still runs under heavy load fine.

cheers

[jeromep]

No, Apple was not that advanced then. If you have a cooling fan on a 603, then it was on all of the time and was not managed by temperature. You might be able to swap the cooling fan for a heat sink from another 603 based machine that didn't use a fan. If you have a fan I can only assume that you are using a PM 6500, as they are the ones I'm most familiary with having cooling fans.

Or better yet, replace the fan. Those high speed 603s could run hot at times and that is why Apple chose overkill on cooling.

[Cipher13]

Your 5500 has a heat sink with a fan that should always be running.

Did you plug it back into the power socket in the motherboard?

I've been thinking of replacing the fan on mine; I want to put a bigger heatsink on there if I can, and also put a fan from, say, a Pentium.

I don't know which fan would be cooler though. Given the temperature 603ev's at the speed of yours (250 MHz) can run at, I wouldn't run it without the fan; especially if you're in a climate as bad as mine.

[saxman]

Thanx for the info guys!

I guess I'll fix it shortly. It is not as hot here as where you are but still fairly warm.

Cheers