"Jon Elson" wrote in message
...

Cursitor Doom wrote:

Hi all,

Anyone got any tips on how to avoid the unpleasant situation where you
try to de-solder a part on an elderly board and end up removing more than
just component leads? Most of the stuff I work on is at *least* 25 years
old and things start to get fragile.
OY! It depends a lot on the quality of the board, and then how much heat it
has been exposed to, over its life.

If the chip is no good, I scribe the leads with an X-acto knife, running
down the whole row, and then JUST BARELY snap the leads off from the body.
You only have to do this on one side of a SOIC. Then scribe the other side
and bend the IC up and down a few times, until it breaks off completely.
Then, the individual leads can be removed in a much more gentle fashion.
Avoid pressing down on the pads, they will tend to "crumple" and the edges
pull up from the board.








I still use a similar method when it suits.
Get a new blade in your knife, and you can quite easily cut vertically
through all the pins on any sized DIL (or SMD) device with no damage to the
PCB, with a bit of practice of course.

(Some SMD devices are glued quite hard to the PCB, making desoldering a
nightmare, but once they have no legs you can safely chisel the body off
the board and wipe away the legs individually)


Gareth.