Eric Auer composed on 2015-05-30 09:08 (UTC+0200):

> However, with your Pentium 4 MAINBOARD, chances are a
> bit better - cap technology has improved since then,

Not materially WRT replacements for motherboards of that period. Newer boards
have taken advantage of design evolution that reduces use of electrolytics in
favor of polymers, and reduces need for caps generally. The major brands have
retired some lines and introduced others, but many of the period that were
used by motherboard makers are still being made. Probably more are than are not.

> so replacement caps of better quality (low ESR, 105C
> temp range) should fit the same mechanical size. Yet

Dell motherboard caps from that period were all of high nominal quality, and
for most, you won't find caps with matching specifications of any better
nominal quality. Dells (mostly made by Foxconn and Intel) used premium major
brands for the most important functions and large physical sizes, mostly
Nichicon, Panasonic and Rubycon. Those from that period that failed were
always 105C and low ESR. The problems for Dell motherboard caps were mainly
two: 1-QC was a problem for a while for one series of Nichicon caps
extensively used (HM series); 2-hot running P4s in SFF Dell cases lead to
marginal cooling that raised probability that heat in any particular
installed environment would be too much for even the best caps to enjoy a
normal life expectancy. IOW WRT #2, Dell SFF designs for a while were under

For the most common motherboard cap replacement selections, it is critical to
select a cap with at least as much ripple and at least as little ESR. In many
cases exact matches to the brand and series are possible, because the
technology did not change WRT the required specs, and they are still
manufactured or otherwise available from reputable sources. Howtos for this
is one of the many great features of If you don't know how to
select caps or perform the soldering surgery, their howtos, FAQs and
hand-holding should enable you to be successful. It even sells premium caps
with the specifications most commonly needed by motherboards.

The description OP gave for the single slightly bulging cap sounds like a
more generic failure, one out of thousands rather than high percentage
failures due to poor production batches. Could be that it's one of the less
important on the board, 6.3V or 10V and 470uF or 220uF or even less.

> mainboards often have multi layer PCB and lots of tiny
> features, so you still have to be experienced to get
> them soldered properly :-)

It can be tricky, but for those unfamiliar with the process yet with
motivation, and any technical skill, like that a ham OP might be expected to
have, the site should lead one through it with respectable chance
for success.
"The wise are known for their understanding, and pleasant
words are persuasive." Proverbs 16:21 (New Living Translation)

 Team OS/2 ** Reg. Linux User #211409 ** a11y rocks!

Felix Miata  ***

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