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Date:      Mon, 9 Aug 1999 18:53:09 -0400 (EDT)
From:      Chuck Robey <chuckr@picnic.mat.net>
To:        Thor Lancelot Simon <tls@rek.tjls.com>
Cc:        alpha@freebsd.org
Subject:   Re: Installing the heatsink
Message-ID:  <Pine.BSF.4.10.9908091850360.373-100000@picnic.mat.net>
In-Reply-To: <19990809181756.A10485@rek.tjls.com>

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On Mon, 9 Aug 1999, Thor Lancelot Simon wrote:

> On Sat, Jul 31, 1999 at 04:38:22PM -0400, Chuck Robey wrote:
> > My alpha came with a heatsink that has what seems to be a thin lead
> > gasket, between the processor and the heatsink itself.  I've never used
> > one before; I've always used silicone grease.
> 
> The gasket is not lead, it is grafoil.  If you've handled it with your
> bare fingers, it's possible that you've damaged it and will need to
> obtain a new piece -- it is allegedly very susceptible to contamination
> with skin oils.
> 
> > Does anyone know if I should use that gasket, and (if so) how should I
> > think use the silicone grease (if at all)?  Is there any rule of thumb
> > about tightening down those two bolts that connect the heatsink to the
> > processor?
> 
> Do *not* use silicone grease.  You need to use the correct grafoil
> gasket, installed without handling with your bare hands (I actually
> just clean my fingers with isopropyl immediately before handling
> the gasket, and make sure they're dry, but gloves are a better idea
> unless you have a large number of surplus alcohol wipes handy :-),
> and cranked down with *the nuts that came with the heatsink kit* to
> the correct pressure, using a calibrated-torque driver.  If you've
> done a large number, you can probably get a feel for "the correct
> pressure", but if not it's best to use the proper tool.
> 
> This is not unlike installing a head gasket in your car's engine -- if
> you screw up, you may not find out until something suddenly blows.  The
> Alpha puts out a lot of heat, and that grafoil gasket, installed and
> compressed properly, gives it a nice uniform path out the top of the
> processor, with no hot or cold spots.  Other methods don't do that, and
> may lead to sporadic misbehaviour that's nearly impossible to diagnose,
> once enough time has passed for it to develop.
> 
> Gasket, heatsink, and nut specifications and torque values are in the
> thick version of the technical manual for your Alpha motherboard.  I
> can also supply them by email if you don't have or can't get that.

I had handled it a *little* before I got the advice (you took about 2
weeks more than other to reply, you must be a little behind in your
mail).  I'm going to go ahead and install it now, but do you know of a
vendor for the grafoil, so that I can eventually replace it?

BTW, getting those little nuts on, inside the heatsink, well it's the
kind of things you damn the designers for.

> 
> 

----------------------------+-----------------------------------------------
Chuck Robey                 | Interests include any kind of voice or data 
chuckr@picnic.mat.net       | communications topic, C programming, and Unix.
213 Lakeside Drive Apt T-1  |
Greenbelt, MD 20770         | I run picnic and jaunt, both FreeBSD-current.
(301) 220-2114              | 
----------------------------+-----------------------------------------------






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