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[email protected] PlainBill47@yawho.com is offline
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Default general question: mainboard caps

On Mon, 20 Sep 2010 12:52:38 -0700 (PDT), Michael
wrote:

Hello,

I've got a couple of Intel boards (D865PERL) that have one bad
electrolytic capacitor each. One board stopped working; the other
still works, but has a bulging cap close to the CPU area. (Pics not
yet available.)

Is desoldering these caps straightforward? Any special precautions
multi-layered PCB traces? Any special gotchas to keep in mind
when ordering replacement caps from say Mouser?

Thanks,

Michael


I've done this on motherboards; it's tedious, but practical. The
suggestions from others are good. Here's a few things I discovered.

While vacuum desoldering tools work well, you have to heat the board
to the point where the solder on the ground lead melts all the way
through the board. The vacuum desoldering tools aren't real efficient
at transfereing heat unless you add a little solder or flux to each
lead you are going to unsolder.

The technique I settled on was to use a 40 watt soldering iron with a
chisel tip. Heat up one leg, add a dab of Chip-Quik, rock the cap
toward the opposite side. Heat up the other leg, add Chip-Quik, rock
cap to other side. Repeat with the heating and rocking until the cap
drops out. While it's still hot, push an iron or stanless steel
needle through the hole (I use a dissecting pick I got in the '60's).
Remove the pick when the solder has cooled; reheat the other hole and
use the needle.

Make sure you keep a chart identifying which cap goes where. Patience
is necessary. Make sure you clean up all stray solder.

PlainBill