Bug #1024 (oscillating re-camping), a possible solution.

[Dima Kogan]

I got a better solution. Like Dieter, I added a 10uF cap instead of
replacing the capacitor altogether. However, instead of using a wire, I
placed the new capacitor directly adjacent to the original cap. If
looking at the photo Dieter sent originally, I placed the cap
diagonally, bottom-left to top-right, with the top-right being soldered
directly to the bottom of the original cap, and the bottom-left
soldered to the can edge. Doing this, the new cap sits directly on top
of some other parts so some electrical tape is necessary below and
above it. On the other hand, this is a very simple way to do the
rework. With this method, I would say the hardest part is removing the
can in the first place.

Dima

On Wed, 10 Jun 2009 17:14:26 +0200
Daniel Willmann <daniel at totalueberwachung.de> wrote:

> Hello,
> 
> On Wed, 10 Jun 2009 10:32:59 -0300
> Werner Almesberger <werner at openmoko.org> wrote:
> 
> > Nils Faerber wrote:
> > > For testing the process I tried to do the rework on a NEO1973 and
> > > promptly got into trouble - I was not able to remove the
> > > capacitor! Is it possible that it is glued to the board?
> > 
> > Oh, so I wasn't the only one with that luck. When I tried to
> > convince Dieter that replacing the capacitor was really easy,
> > I decided to give it a swift try on one of the GTA01
> > pre-production units I have and then brag about it.
> 
> let me brag instead. :-)
> 
> > My first try was the "single iron, lots of solder" attack.
> > To my great dismay, the cap didn't budge. I then went through
> > all my electronics torture chamber has to offer, hot tweezers,
> > etc., with pretty much the same lack of result. In the end, I
> > reduced the problem to a simple mechanical one that could be
> > solved with a dremel.
> 
> Okay, harsh measures...
> I've since reworked about 6 or so (all various GTA02 versions - A5/A6,
> MP and prototypes) and I managed to get the cap off on all of them. I
> have to admit that it's not too easy, though.
> 
> Be aware that the right side of the cap is connected to the
> groundplane, so you need quite some energy in order to get it to heat
> up enough. There could also be glue in the mix, but I'm not sure how I
> could check that.
> I usually heat up both sides with two soldering irons wait a little
> and then try to move it around a little on the board until it's
> loose. Then I gently lift it off while holding it between my two
> soldering irons.
> 
> 
> Regards,
> Daniel Willmann