On Jan 13, 6:37*pm, John Rumm wrote:
I was toying with doing a wiki article on component level repair of
electronic stuff, since there seems to be so much otherwise decent kit
that dies these days for silly reasons like failing capacitors etc.

With modern lead free solder, and ever increasing layout densities, use
of multilayer boards etc, the job of component removal seems to be
getting ever harder. There was a time when a moderate iron with enough
bit mass to heat the joint quickly, was all you needed. To reflow the
joint and then either pull the device, or apply a solder sucker, all one
did was tin the bit, apply heat for a couple of secs, and job done.

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?

--
Cheers,

John.

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Desoldering braid. Like co-ax braid but loaded with rosin (although I
think there is also a plain braid).
Flux, either a bottle of wet for use with a cocktail stick or artists
brush or a pen type.
Mechanical pencil. Clears the wet hole.
Tip cleaner, wetting and fluxing. The greater the cleaned surface
area of the tip, the more solder it will draw.
Bulb type sucker, which can be reserved for blowing. They don't have
the draw capacity of the sprung syringe but they are easier and
quicker to place because the hand may be stabilised by resting upon
the board.
Scrapers and point tools, to remove dry blobs.
I also like to use a gas iron which seems to have a higher heating
rate on a small bit, and I can switch hands without bothering with a
wire or getting my snozzle over the work.