If you know where the shorts are you may be able to blow them by
passing a high current through the short.
Keep the voltage low & you minimise the chance of damaging anything
else but it is a risky process. I've had mixed results but have fixed
a problem caused by a short inside a void in a multilayer pcb using
the prcoess.

Alternatively
After using the soldersucker to remove as much solder as possible you
can generally free the pins by pushing them sideways with a small
solderining iron tip. Once all are done then you can pull all pins
through.

Or the opposite method
Run as much solder as you can onto the pins and keep the whole lot
molten by running the iron backwards and forwards to create a pool
along the pin line. Once everything is hot enough you shpuld be able
to pull out the pins. Clean up with a soldersucker and/or solderwick.

Your milage may vary.

Richard P

On 19/03/06, Ruben J=F6nsson <ruben@pp.sbbs.se> wrote:
> I would try to cut the stip connectors with a fine side cutter, pin by pi=
n to
> separate the two boards. Then desoldering each pin, one by one at the sam=
e time
> as pulling them out with a plier. If the strip connectors are held togeth=
er
> with some plastic, cut it of first so the pins are totaly separated.
>
> / Ruben
>
> > I've got a display module that I designed and built that consists of two
> > double-sided PCB's sandwitched together. One PCB has 35 5x7 LED modules
> > on it, the other PCB has the driver circuitry. The former PCB is
> > entierly through hole while the latter is almost entierly fine pitch
> > surface mount, soldered using a toaster oven. The connection between the
> > two boards is made by in-line strip connectors, soldered to both boards.
> > 72 individual pins in total go between the boards.
> >
> > In short, the gap between the boards is about 0.100" and getting them
> > apart is going to be a real pain. I did carefully check that none of the
> > protruding pins from the through-hole components are shorting anything,
> > that is not an issue. I really need things to be compact in this
> > application.
> >
> > The whole assembly works perfectly except... Somewhere on the LED board
> > there are two shorts, between two pairs of column lines to the LEDs. I'm
> > pretty certain that they are caused by tiny solder bridges, the layout
> > of the boards was very tight in some areas.
> >
> > Any clever tricks you guys can think of to fix this, short of taking
> > everything apart? I'm half inclined to try simply running everything
> > through the reflow oven again, but the LED modules would probably melt.
> >
> > And if I am going to take things apart, how the heck do you reliably
> > desolder pins from through-hole plated circuit boards? I've always found
> > the solder sticks too well for solder-wick to remove it. Using those
> > solder suckers is a nice theory, but the joints cool before I can
> > position them and release. Unfortunately if I manage to damage any of
> > the pins, I've really got to then take off the led modules to solder in
> > new pins as the joints are obscured...
> >
> > Somehow, after looking at how compact Cray's were built, I think they
> > had better pre-assembly testing than I did!
> >
> > --
> > pete@petertodd.ca http://www.petertodd.ca
> > --
> > http://www.piclist.com PIC/SX FAQ & list archive
> > View/change your membership options at
> > http://mailman.mit.edu/mailman/listinfo/piclist
> >
>
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D
> Ruben J=F6nsson
> AB Liros Electronic
> Box 9124, 200 39 Malm=F6, Sweden
> TEL INT +46 40142078
> FAX INT +46 40947388
> ruben@pp.sbbs.se
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D
>
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> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>

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