[ale] Bad capacitors in computer motherboards

[Randal Jarrett]

Bad caps can cause all kinds of erratic behaviors according to what part
of the motherboard that they are in.  The physical signs are usually
swelling, leaking and sometimes heating. If they go bad in the power
filtering section, (usually around the power connector and regulator
transistors that are soldered down on the mb) they cause erratic
fluctuations on the voltages which will cause ICs to behave erratic.

In other words, all kinds of nasty and unusual problems. 

On Wed, 2006-11-01 at 12:49 -0500, Michael Smith wrote:
> What are the signs of a faulty capacitor?
> 
> <Begin Short Rant Here>
> I ask this because I had an ASUS P5RD2-VM board that I just sent back to
> newegg that would crash randomly.  I thought it might be a driver but it
> started crashing in safe mode in Windows XP.  I couldn't even install any
> type of linux on it.  It would hang when copying the files over to the
> hard drive(on ubuntu, fedora, and suse) from the CDROM.  I ran several
> memory testing tools and all tests resulted in no errors.  I ran prime95
> in XP and it never would crash ehne I ran it(and the temps remained pretty
> low) but if I left the computer on for a day it would crash.  I debugged
> the memory dumps in XP and they would show different error locations.  I
> tried removing all hardware except for the CDROM, memory and hard drive
> and it still crashed(the mb has on board video).  I tried swapping hard
> drives, power supplies and various cables also. Since it would crash after
> several hours I thought that it might be heat related but after logging
> the mb and cpu temps to a file I realized that the temps were well within
> the normal range.
> Anyways I sent the memory and the motherboard back because I couldn't
> resolve the problem.  I tried for 2 months to get it working.
> </End Short Rant Here>
> 
> 
> > Several motherboard manufactures had a bad run of caps (gray market)
> > that went bad in a short time.
> >
> > Check with the maker of your mother board as most of them will fix it
> > for you.
> >
> > I've had an Asus and a Abit repaired.  What they do most of the time is
> > to send you an exchange mb right away.
> >
> > On Tue, 2006-10-31 at 12:45 -0500, deritchie at earthlink.net wrote:
> >> Chris,
> >>    if you are looking for bad capacitors, the best device to do this
> >> with a ESR meter. ESR stands for
> >> Equivalent Serial Resistance - as electrolytics go bad, this rises over
> >> time. The good news is that the
> >> replacement caps are relatively cheap and easy to replace if you are
> >> handy with a soldering iron....
> >>
> >> -- Dave Ritchie
> >>
> >>
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> > --
> > Randy Jarrett  K4RSJ
> > Randy's Ham Shack
> > <rsj at radio.org>
> > FWD# 654871
> >
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> >
> 
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-- 
Randy Jarrett  K4RSJ
Randy's Ham Shack
<rsj at radio.org>
FWD# 654871