Solid caps can blow up?

Gee, you forgot to cross-post to alt.scorekeeping.idiots and rec.games.ropeadope.

Inrush can kill any electrolytic capacitor. Some are more sensitive than others.

Phil Hobbs

¡Ay, caramba!

Make in England?

What?

It wasn't inrushing at the time. The card had been running without a restart for a week or two. It's been running flat out 24/7 for the last year doing astrophysics stuff on Boinc.

I've never seen one of those break though, they're always the coloured wet electrolytics that burst at the end and leak brown fluid.

"Polymer electrolytic capacitors are also available in a hybrid construction. The hybrid polymer aluminium electrolytic capacitors combine a solid polymer electrolyte with a liquid electrolyte. These types are characterized by low ESR values but have low leakage currents and are insensitive to transients,[1] however they have a temperature-dependent service life similar to non-solid e-caps."

It would appear, sadly, that we cannot rule out the presence of liquids in the stupid things.

Paul

alt.comp.os.windows666 etc aren't super related to a computer repair problem, I wouldn't have thought.

Looks pretty wet to me. Sticking that right next to the (apparently inadequately-sized, and certainly inadequately-vented) heat sink for the SMPS switches isn't a recipe for long capacitor life.

Cheers

Phil Hobbs

Can I tell from the markings which type it is?

There are computer people in there.

Why does it concern you anyway? Just hit reply.

What do you mean? If you're talking about the mess to the right, that's actually a piece of copper track for the ground that's burnt off the paint above it.

Well it has to go somewhere, there's a lot of hot stuff on graphics cards. It also probably needs to be close to the other VRM stuff. Trouble is all these caps are also under the big heatsink for the main GPU which gives off up to 250W. That heatsink covers the whole card, there is nowhere cool.

The caps in the photo are wet electrolytic, but dry caps can also explode - Tantalum orange drop caps were notorious for that in 70s equipment.

John :-#)#

I thought the ones in the photo were dry. What makes you think they're wet? I thought the wet ones were these kind with vents:

Based on symptoms, there have been cases of capacitors that needed vents, not getting vents. This was someones attempt at capacitor fraud, selling cheap electrolytics in polymer form-factor casings. (This was going on, early in the intro of Polymer caps as a replacement for electrolytics.)

Companies do this, if they think they can't be sued.

When caps can fail on gas pressure, they have a K or an X stamped in the metal top, to promote venting at sufficiently high pressure. The rubber bung on the bottom can also push out, as a relief mechanism, but is not the preferred solution. It's better if the vent opens.

When the pH inside an electrolytic is wrong, it eats through the K or X area and there is a stain on top. The failed chemistry, even works without bias. The juice can eat through in 1-2 years of sitting in the box.

*******

If intending to run a vid card at max power forever, it pays to do a visual analysis and decide whether you want to fit a third party cooler kit (with better surface blow-down characteristics). In the year 2022 however, the picking are slim, so this is no longer an option. One of the companies good at making those, has stopped. And COVID was only one factor in the decision. Even if you buy a water block kit, the board might still need air cooling for the VRM section.

Paul

By chance, was it in backwards?

"Paul" snipped-for-privacy@needed.invalid wrote

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Here's the real link without the imgur BS:

I once had a case where one of those blew up. I was putting in a CD player. Apparently there was a short somewhere inside the player. I smelled electrical fire, but before I could do anything it blew up, taking all the components f the computer with it. Everything got fried.

Is this a gaming machine? Overclocked, overstressed, cheap, and fundamentally useless?

Should have posted to alt.comp.hardware.pc-homebuilt?

Yeah, that was a great project--one of my favorite things is to do something novel and useful with practically zero apparatus.

It was also my first actual embedded system--if you look at the war story paper at

, you'll see why that was. ;)

Not that I know of, sorry.

I had considerable interest from ARPA-E back in my early consulting days (2009ish) for making cheap handheld thermal imagers to look for heat leaks in buildings, but back then they didn't have any discretionary money the way DARPA has.

Back then the Measurement Specialties Inc. engineer I worked with (Mitch Thompson, may his tribe increase) had risen to be CTO of Tyco Electronics, but even together we couldn't get MSI to build the films for them--they were only interested in motion detectors.

So the Footprints technology has sat there from that day to this, unfortunately.

Cheers

Phil Hobbs

Those tend to be infantile failures.

Regardless of how solid or less solid electrolytics are, they can and do blow. Sometimes in a spectacular manner. As a kid I had a big one almost the size of a coke can lift off and whizz by my right eye at less than

2" distance. It hit the ceiling and took some plaster out of it, fell back onto the carpet and smoldered a nasty burn into that.

If the black ribbed thing is a heat sink and gets quite hot then the placement of these caps so close to the heat sink was not a smart move on the part of the design engineer for this board.

Just about anything can be made to "blow up", provided one can find a way to impart sufficient energy within a narrow enough time window.

So, one little cap, shorting, will dissapate something near, or greater than, 2.5kW for the short time before it blows. 2.5kW of dissapation in that tiny space is more than enough to cause significant damage, including "blowing up".

Note - removed irrelevant windows groups from Newsgroups: header.

Even on a decent thing like an AMD GPU?

Most of them are not actually inside computer cases, they're sat loose on shelving, so they have a nice cool air intake. They're connected via USB extensions either to a PCI-Express slot, or a multiplexer to connect 4 into 1. It's the first time I've had a failure there. I have blown some surface mount transistors on others, on the rear (non-fanned) side, in the power regulation area.