[rescue] E4500 questions

[Michael Horton]

given time (heat, etc.), the glued heat sinks will fail also.

the glue bakes, becomes brittle, and cracks.


-----Original Message-----
From: rescue-bounces at sunhelp.org [mailto:rescue-bounces at sunhelp.org] On
Behalf Of M Thompson
Sent: Monday, September 06, 2004 8:17 PM
To: rescue at sunhelp.org
Subject: Re: [rescue] E4500 questions


>heat sinks also just come loose with "age".
>i have this happen to a dozen of these system boards just
>sitting/running in servers that were never moved after installation.
>
>sun told me the "glue" loses its ability to hold the heat sinks in
>place (and, if there are plastic clips, they get brittle).
>
>i have had this happen to least a dozen of these system boards.
>
>sun replaces the system boards if they are under contract
>(and i have replaced a dozen of these system boards).

There are two designs of boards. The early ones have heat sinks that are
made by TYCO. These have a "C" shaped base that clips over the chip and
the heat sink screws into the base. There is a very small tang on the
base that holds it onto the chip. A very small shock can break the tank
off and the heat sink comes loose.

You can scavenge heat sinks from a donor board by unscrewing the heat
sink, sticking a small screwdriver into the slot at the side of the
base, carefully prying the tang away from the side of the base, and
lifting the base off the chip.

The newer boards have a heat sink that is glued to the chip. I haven't
seen the glued ones fail yet.

Michael Thompson
E-Mail: M_Thompson at IDS.net
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