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Old August 9th 03, 07:59 PM
Bob Fleischer
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Default Presario 2701US overheating, heatsink and fan problems

I have a year and a half old Presario 2701US laptop running Windows XP Home.
Over the past few weeks the system has been just shutting down (needing
a complete reboot) with increasing frequency. It got to the point where I
could rarely get it to start up completely, and doing something like
inserting a CD or DVD might cause a shutdown.

One symptom that preceded this is very erratic operation of the fan --
usually at very high speed (loud fan noise).

Thanks to a reply in the Compaq support forums, I found that the Evo N180 is
essentially the same unit and I was told the location of a downloadable
service manual for the N180. Thus I was able to disassemble the unit.

I found a number of surprising problems with the processor heat sink and fan
assembly. The processor fan has a cable that connects to a connector on the
main board, but the electrical connection between that connector and the
board was not soldered -- just "touching" -- and was definitely
intermittent. With some delicate soldering, I was able to get a reliable
connection. The fan now runs in a way that seems "normal" and the system is
running better now.

It's too soon to say the problem is fixed, and another problem has me quite
worried: the mechanical mounting of the processor heat sink.

The heat sink mounts with four screws that go into threaded "nuts" that are
soldered to the main board. One by one the threaded "nuts" have become
loose from the board -- the solder bond has broken. Is it usual for a
massive mechanical assembly to be mounted by solder like this -- especially
in a mobile device?

Thus, the heat sink is not really fastened to the board right now.

I have been afraid to try to solder the "nuts" back to the board, since a
lot of heat will be needed -- my pencil soldering iron can't heat them
enough (although I have a 100 watt "gun" I could use). I'm afraid this kind
of heat will damage the board -- should I fear this?

Any suggestions for alternative to soldering? Heat-conductive adhesive?

--
Bob Fleischer
Groton, MA 01450