Subject: CPU / cooling / torques etc
To: port-alpha list NetBSD <port-alpha@NetBSD.ORG>
From: Wilko Bulte <email@example.com>
Date: 06/10/1998 19:08:54
as promised I paid a visit to the Digital repair facility to ask about the
heatsink mounting on an AXP CPU.
In talking to an expert :
- in the repair facility they use a small torque wrench
This is done to really adhere to the spec, and to avoid goofups. Not
every repair technician has 'sensitive' fingers.
- they always replace the aluminium nuts, just to be on the safe side.
Another guy might have overtightend them before. In a -hackers situation
this should normally not be an issue.
- they also replace the Grafoil heat transfer sheet that is between the CPU
and the heatsink. In my own experience (AXPpci33 & Jensen) the Grafoil
was undamaged. Just handle them with care.
- enough torque is essential for a good heat transfer. Small wonder.
The heatsink is an overdesigned job, so there is some slack. Slack gets
bigger when you add a fan.
- don't overtighten, you can crack the chips enclosure. We obviously
already knew this, but this guy saw real life examples.
- LCA chips are not really known for their tendency to overheat with a
sensibly 'torqued' heatsink. For hobbyist use a 'fixed is fixed'
In summary: use common sense and there should not really be an issue.
Hope this info is of any use.
| / o / / _ Bulte email: wilko @ yedi.iaf.nl
|/|/ / / /( (_) Arnhem, The Netherlands WWW: http://www.tcja.nl
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