10 Sep
2011
10 Sep
'11
2:49 p.m.
-----Original Message-----
From: Martin Bishop [mailto:mjd.bishop at emeritus-solutions.com]
Sent: 10 September 2011 13:08
To: General Discussion: On-Topic and Off-Topic Posts
Cc: Rob Jarratt
Subject: RE: Desoldering (Again)
Rob
I'm not surprised you are struggling : a non trivial evolution
I'll presume that we are talking DIP, and that you can't cut the legs off
-
as
removal without damage to either PEC or device is
required. If the chip
is
"toast"
It actually is partially working, it allows the board partially to work, so
I want to keep the chip in case my replacements don't work (I am going to
solder in a socket).
then cut the legs close to the package (e.g.
Lindstrom 7191) and remove each leg / clean up each
via individually using
the same methods but with better access and 14 easy rather than 1
difficult
problem.
Things which may work include:
- solder (sucker) pump
- resoldering almost dry joints, to get them dry on the next attempt
- lots of flux : flux pen, liquid, gel, jelly (highly recommended)
- solderwick rather than a solder pump
Things which will work:
- Pace SX-90 Sodr-X-tractor or similar hi-end tooling (my experience is
that
inexpensive and poorly maintained extractors are
useless) The technique is to oversolder the joint, suck it dry while
wiggling
the pin with the tool to preclude adhesion to the
via's barrel
- a visit to your local wireman (who has the tooling)
I'm in Dorset UK; contact me off list if my SX-90 can help
Many thanks for the offer, but I am in Manchester, so just a little too far
away! I'd post it, but I need the board quite soon and may just put it back
the way it was until I have done what I need with it and then perhaps I
could send it.
I don't suppose there is anyone in the Manchester area who can help? Is
there some way to find a "local wireman"? I don't know any.
Thanks
Rob