[c-nsp] Heat guns: was: New PIX DoS Vunlerability?

[Jay Hennigan]

On Fri, 1 Apr 2005, Matt Hill wrote:

> Jay typed:
>
> The 506
> seems to be a hardware failure, probably thermal.  I may try the
> heat-gun
> and freeze-spray trick on the PCB if I have the time.  Replaced with a
> new one, identical config, no problems.
>
> What is this method you speak of?  It sounds rather dodgy to me
> personally.  If something has been damaged due to environmental issues
> isn't it permanent?  However if this is a magical fix for all heat
> related issues then Id love to hear it.

It's a troubleshooting method used to isolate hardware defects that
fail when either hot or cold.  You warm up a small area of the circuit
board with a heat gun until it fails, then selectively cool the parts
until the failure clears up.

Doing this can identify the defective chip or other component, which can
then be replaced.

This is old-school.  Modern electronics is very labor-intensive to rework
compared to the cost of robot-assembly of a whole new board.  So other than
for hobby/curiosity purposes it's usually more economical to just replace
the whole circuit board or device than to repair to the component level.

--
Jay Hennigan - CCIE #7880 - Network Administration - jay at west.net
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