OT: Removing Electrolytic cap residue

[John Boffemmyer IV]

Ok, working on thousands of mobo's and PC's (ick, i know) over the past 
decade, I must agree and disagree. Most Asus and Tyan boards have been ok, 
but, about 3-4 years ago, they also had the bad cap issues. The Asus A7V 
(early Socket A AMD Athlon/Duron line) and some of the 266 series had a 
leaky cap/cap failure issue for a while. Ended up replacing about 20 or so 
boards because of this (shop was too cheap to just replace caps when 
another board was on hand and took less time to swap boards than to fix the 
damned problem). As with the Tyans, some of the P-III socket 370 boards 
from 2000-2002 had such an issue as well, though, less so than Asus and 
obviously, much less than other manufacturers, such as Abit (the whole 
KT7/KT7A series was known to be an 8/10 failure rate for that time frame. 
later revisions, I believe called the 1.3 to 1.6 revisions, did not have 
these issues as different caps were used.).
As far as I could remember, if the caps leaked that badly, there was a good 
chance that there was damage to other circuitry on the board and any 
attempts to repair should just go to replacing the board at that point to 
limit headaches from voltage and circuit instability caused by voltage flux 
from the bad caps. Once had an Iwill board in the shop I had worked in do 
that from caps going bad and could not figure out why it was giving errors 
in diags/Winblows until we re-examined the board with a magnifying glass 
and swapped out all the other components (ram, cpu, vid card, etc) and 
found there was a small trace going from an area near one of the caps to 
the northbridge that was a bit messed up. Replaced the board and things 
were still a bit messed up, had to replace the ram too and then everything 
cleared up.
Voltage flux is nasty as sometimes, it is an unseen killer of parts. Best 
bet, if unsure if stuff is still safe, replace it and let someone else 
worry about headaches.
-John Boffemmyer IV


At 07:32 AM 4/5/2005, you wrote:
>On Tue, 2005-04-05 at 00:58 -0700, Eric Smith wrote:
> > Adrian wrote:
> > > A friend of mine has a problem with Electrolytic caps on his motherboard
> > > having gone "pop" & deposited their contents on some contacts...
> > [...]
> > > Does anyone know how best to remove dried capacitor electrolyte from a
> > > surface?
> >
> > I don't know, but my solution to this has been to replace the affected
> > motherboards.
>
>If the motherboard is "valuable" in some way (containing the right slot
>layout for the user, or having a decent BIOS, or onboard SCSI or
>something) then one option might just be to replace the damaged PCI
>slot.
>
>I've never tried this, but it can't be much harder than snipping a dead
>IC from a board, cleaning everything up, and replacing. Either buy a new
>PCI socket from a component place, or try removing one from a dead
>motherboard. I've never tried the latter (only with ISA sockets) - but a
>blowtorch on the underside of the donor board might do the trick without
>damaging the PCI slot....
>
> > I'll note that I have never seen this problem with any of my Asus or
> > Tyan motherboards
>
>FWIW I've seen it on a couple of dual-CPU Asus boards before now (but
>have seen other Asus boards from the same era that have been fine).
>
>cheers
>
>Jules