On 13/01/2012 18:55, tony sayer wrote:
Recently I have needed to recap a few motherboards (not usually an
economic exercise - but these were custom form factor jobbies where
replacements are not readily available), and they were a right PITA to
work on. Obviously multilayer, and since the caps are on the power
regulation sections, probably connected to fairly heavy power plane
traces in the board. Component removal was very difficult - often taking
excessive time for the joint to reflow. Tight pins in close holes with a
small annulus. However cleaning the holes for reuse proved impossible
with any of my normal irons. In the end I had to resort to using a hot
air paint stripper with small nozzle on the end to get enough heat into
the area to be able to suck the holes clear!

I was wondering what suggestions those of you who do this daily had to
offer?



We had a similar problem on a Harris VHF/FM broadcast transmitter where
they recommend you break the cap off and solder to the wires that are
left behind;!..

Hmm nice ;-)

Still in the past when I have needed to remove a QFP device off a board,
it was safer to run a knife down each side a few times to chop off all
the legs, and then flick each off individually after rather than try
doing the whole thing in one hit. Bit of a shame if the device was not
toast before you started though!

This wasn't to do with cleaning out the holes just a lorra dismantling
to get to the other side of that board. Prolly not too practical on
Motherboards with very high component densities, but as you say a real
PITA to clear the holes..

Actually a workable solution - although difficult getting cutters under
them sometimes. You can sometimes get a scalpel blade in there.


Just bought a new Gigabyte board the other day boasts "solid" Electro
caps;!...

Yup, some of the ASUS ones are now claiming mil-spec caps in full ali
enclosures rather than the normal plastic coated ones.

--
Cheers,

John.

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