Re: Putting together a computer from old components

On 11/29/2021 2:42 PM, Marco Moock wrote:
> Am Mon, 29 Nov 2021 14:34:56 -0500
> schrieb Paul <[email protected]>:
> 
>> One of the problems with older motherboards, is the "bad cap" problem.
> If these are through-hole caps you can solder them out and replace
> them, I often do that if a cap fails.
> 

There are a couple ways to fit electrolytics.

One company I worked at, used "generous holes" for caps. They
set up the automatic insertion equipment to "form" the legs. This
allows the caps to be held in place, by a bit of spring tension.

The caps on such boards, are dead easy to remove. Remove the
solder from a hole with the solder sucker, and the leg comes
out without too much difficult.

The second cap mounting method is "interference fit".
Only five thou clearance between leg and pth. Once filled
with solder, even with a vacuum desoldering machine, they're
almost impossible to remove. You could try ChipQuik, you
could take your Dremel and just grind the cap off the
board. There's lots of stupid stuff to try. But when I
tested with our vacuum desoldering station, multiple attempts,
I couldn't get them out (without being abusive, and you
can't be doing that to customer boards).

So yes, sometimes, the caps do come out. But if you want to
run a business re-capping boards, there will be days you'll
regret your business model.

    Paul