[rescue] Replacing CPU cooler fan on ultra 1

[Jonathan Groll]

Mike Nicewonger wrote:

>Every Ultra 1 I ever saw with a fan on the CPU had the 'fifth' screw. 
>What I've done is replace the fan with a similar sized one off of a 
>PeeCee heatsink of some sort. Just remove the 4 screws then remove the 
>fan. Then just slide the replacement into place and leave the 5th screw 
>where it is. I just rebuilt the fan setup on 4 U's I will be putting 
>
>  
>
Great idea, I think your way is better than mine.

My original thoughts were to just leave the broken fan in place where it 
was and add another big fan on top of that above the plastic shield. 
This should have (a) extracted  the heat anyway (b) the airpressure 
should have made the broken fan spin.

However, what I didn't take into account was that the cooling of the 
cache control chips might be weaker:

>That plastic cover channels air toward the heatsinks on the cache 
>control chips. 
>  
>

Isn't it strange that the original Sun designers didn't seem to want to 
take into account common component break down - cooler fans will 
eventually breakdown, NVRAM batteries will go flat....

-Jonathan