Al electro's vs polymer?

I think using three caps can be evidence of Muntzing-design, not necessarily reliability-design. Use three cheapo 47uF caps in parallel where you need 150uF that also handily combine correctly to provide the ESR the control loop needs.

now you also have three points of failure instead of one (costly) 150u with a better ESR and temp spec

You can do that in your own projects or if you work for the defense/military contractor (or those Xtreme Fat1tly $1000 PC PSUs for gamers) but nobody is ever gonna use three 330uF caps for a 500 in a general consumer price-point oriented product, though.

Don't think they had any choice in the IIci era but to distribute the caps because, in the vernacular, even the plain-Jane Al electros available at the time sucked balls compared to what's available now.

Meh, in consumer equipment they use three 100u where they need a 330, they all run hot, one starts going much higher ESR sooner rather than later and the supply dies.

Tolerances on capacitors can be +50, -20 %; if you 'need' 330u, three 100u won't do it. Having tolerance if one fails high-ESR would have been a good bet during the capacitor plague (which cost warranty centers many hundreds of megabucks).

Component failing isn't the bad thing; functional failure of the system is. Avoid it with component quality (uncertain: refer to the capacitor plague), or with redundancy and overdesign, or... run into functioinal failure.

+50% vs - 20% and the maybe the distribution skews to high and you get three spins on the wheel? sounds like an excellent opportunity to save 20 cent on each unit with a 99% confidence each one end up with just about what it needs, perhaps

bitrex wrote in news:Ipy9F.223047$on8.146436 @fx46.iad:

The PS feeding the MOBO matters too. Those local supplies work better if the DC feeding them is robust and clean.

So if you went and bought a POS cheap PC power supply, you are part of the problem.

Especially if you also run a good high end vid card, and that means a good PS is 100% required.

I say this because my 12 core server runs fine at all CPU tax situations. I see no heat and even after high end benchmarks get run, much less doing fractals and 3D renderings, etc.

So if you are one of those 'just enough to make it work' power supply guys, you cause many of your own problems.

Yeah, but engineering doesn't require half the box to do all the job. Cray-1 power supplies were brute-force unregulated DC; the differential logic didn;t modulate the power any more than a resistor load would have.

This pc uses a bank of 1000uF caps in the onboard volage converter. I know cos eventually I replaced em all. It's not unusual for PCs to do that. It didn't fail to work until almost all that capacity was gone, so it's just done for reliability.

NT

whit3rd wrote in news: snipped-for-privacy@googlegroups.com:

Their systems were not powered the way these motherboards are with immeiately proximal dc-dc conversion being part of the heat product.

They operate better and more efficiently with a clean DC in feed. So less heat would be on those parts doing their jobs just a slight bit easier.

DC to DC supplies are unhappey when the DC IN component is full of PARD, ripple, lulls in regulation, etc.

snipped-for-privacy@gmail.com wrote in news: snipped-for-privacy@googlegroups.com:

You sound like SkyTard Farting does. Except he is way too dumb to actually repair the stuff he breaks.

You replace a lot of EL caps in your crap? What do you buy old used gear?

Do you bake your stuff in an oven so often you have to replace the caps?

If you had half a brain you could answer those questions yourself. I've had this thing running for years, it was a top of the line system & still doesn't need replacing. It's still quicker than many new machines. It's done well.

NT