Advice on Desoldering an IC

[Peter Coghlan]

I had to desolder a fairly large number of 14/16 pin ICs from a two layer
PCB recently.  I had an basic soldering iron and a spring loaded solder
sucker thing.  I also had some wick but never having had good results with
this, I decided not to bother trying it this time.

I was aware of the idea of cutting the pins to make removal easier but I
preferred to keep the ICs intact in case they turned out not to be faulty.

My first attempt was pretty bad and did quite a bit of damage.  By the
tenth time around, I was making a much nicer job of it so what worked
for me was practice.

I ended up propping the PCB up vertically, placing the sucker squarely over
the joint on the solder side, heating the IC pin on the component side with
the soldering iron and releasing the plunger in the sucker after allowing the
solder a little time to melt.  Sometimes this cleared all the solder out of
the hole but usually it did not.  I found it useful to get the tip of the
solder sucker to seal well around the joint with little or no gaps for air to
get through.  I kept going around the pins until I could see through most of
the holes when holding the board up to the light.  At this point many of the
pins were still stuck to the sides of the holes so I then applied the
soldering iron to each pin in turn on the solder side, pushing the pin gently
away from the side of the hole.  When the solder melted, the pin would then
move to the centre of the hole and sometimes come free entirely.  Then I would
go back to the first procedure with the solder sucker to clear more solder out
of the holes.  Using no more than finger pressure, I would try to pull the IC
out while dabbing the soldering iron on any joints that seemed to be still
holding it in place.  After a several interations, the IC would pop out, maybe
at one end only first.  A bit tedious and not at all quick but it worked well
enough in the end.

Unfortunatly, the next time I have to do some desoldering, I will have
probably forgotten what worked well this time and have to learn it all over
again.  I will probably also forget that it would be useful to get some
practice in first...

Regards,
Peter Coghlan.

Rob Jarratt via cctalk wrote:
> I am trying to remove an IC from my PDP 11/24 CPU, a DS8641. I am really
> struggling to desolder it. I am using the technique of applying fresh solder
> and then removing it. But after multiple cycles of this I think I am
> starting to damage the PCB.
> 
>  
> 
> I am using a fairly cheap desoldering station (this one
> https://cpc.farnell.com/duratool/d00672/desoldering-station-uk-eu-plug/dp/SD
> 01384?st=duratool%20desoldering). Its spec in terms of vacuum pressure is
> equivalent to that of the professional Hakko ones though. I am also trying a
> hand desoldering pump. None of these are able to clear many of the holes of
> solder, although some are doing better than others. Nevertheless, the IC
> remains stubbornly unmoving.
> 
>  
> 
> Are there any tips for removing ICs?
> 
>  
> 
> Thanks
> 
>  
> 
> Rob
>