10 Sep
2011
10 Sep
'11
2:59 p.m.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of Chuck Guzis
Sent: 10 September 2011 16:30
To: General Discussion: On-Topic and Off-Topic Posts
Subject: RE: Desoldering (Again)
On 10 Sep 2011 at 13:08, Martin Bishop wrote:
repair
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'll add that a temperature-controlled iron is essential for any kind of
work; inexpensive irons just generate too much heat
and lead to damage of
the PCB.
Another thing to consider is using Chip-Quik (or any similar fusible
alloy) to lower the temperature of the solder holding the IC in place.
This
greatly reduces the chance of damage to the PCB
traces.
When I'm working at repairing SMT PCBs, CQ is a standard weapon.
--Chuck
What I am not clear on here is if the two suggestions go together
(temperature control and chip-quik or similar). It sounds like you are
suggesting either on their own would be good, but I assume the idea is to
use low temperatures to avoid damage, and because of this you need to use
low melting point solder to desolder. But surely you need higher temperature
to melt the original solder first? Sorry, but I am still not experienced
enough to understand this.
All the same, it seems like I need a better iron in any case, I have failed
to desolder another component on another board (Tony knows which one I
mean), possibly in this case because the iron is not hot enough because
there is a lot of solder around the component. For an occasional repair type
of person like me who can't justify spending hundreds of pounds on this
equipment, what is the cheapest iron I should be thinking of?
Regards
Rob