Solid caps can blow up?

I've set fire to water. I watered a plant behind my 70s stereo amp while it was off and some got inside. Assuming it would have dried out when I used it next, I turned it on and received loud mains hum on the left, and music on the right. This was shortly followed by steam, then smoke, then flames inside the unit. About eleven components were destroyed so I gave up on it. I'm guessing mains shorted into the amp input and everything overloaded?

I used to blow them up for a laugh, but outdoors. Many ended up in neighbour's gardens. The best was a 15V 53,000uF slightly bigger than a coke can cap. The bang caused ringing in my ears. There was no vent on that, until it created its own one.

You can get a nice smell off them if you blow up lots at once. I was an IT tech at a school where they were renovating and building an extension. Irish (ROFL) electricians confused the wiring colours from the old UK stuff and the new EU stuff and put 415V into a classroom instead of 240V. It was the woodwork department where they had three phase lathes, but also one phase computers, 20 per room. The power supplies in the old imacs didn't like 415V and simultaneously exploded, sending smoke everywhere. The teacher phoned me completely confused as to how so many computers would fail at the same time. The only thing that survived was a ceiling mounted projector I'd installed myself, with a surge protector plug. The plug had become a pile of molten plastic, but protected the projector. I claimed on the electrician's new for old insurance policy, got 20 brand new computers, then replaced the caps in the old ones.

That's not what heats the caps. Above them (5mm away) is a 10 inch by 4 inch by 1 inch heatsink with two 80mm 5000rpm fans to cool a 250W GPU. I guess there is no cool place to put them.

It chose to do this itself.

I have such a large supply as I have around 12 graphics cards all running at once. Easier to have one big 12V rail.

The input to my house currently reads 243V, 26.4A.

I'm hoping to repair it....

It (the capacitor) made no such choice, as it lacks consciousness with which to do so.

Instead, wear and tear, likely heat related, resulted in it eventually shorting. And once it shorted, it then dissapated sufficient energy within a narrow enough time window to blow up.

True. I have seen a few make it awhile, but it is very unusual.

I saw "16V" on the top. If it is facing

12V, then it is not much of an over rating. But it might be facing 5V.

It could also be "poop happens".

2.KW power supply. Is he arc welding with it?

The choice then was made by the designer who cut corners and didn't care if it exploded after 10 years, since it only has a warranty for 2 or 3.

The worst one I saw was a compact fluorescent animal UV lamp from China. The capacitor burst after 3 months use. So I put in a bigger one (higher voltage and low ESD). It seems to be happy now. Still, it was £7.50 for the lamp and the proper ones from big companies are £20-£30, which I've also had fail. Again, heat. Almost an absolute lack of vents on the chassis.

What I don't like about that area, as a co-factor, is two connectors carrying a lot of amperes for the +12V and the board is probably using half ounce copper. It could be that a track traveling near the capacitor, contributed to the local heating effects. Sometimes, the exit area near the connectors needs via-stitching to try to spread the current better into the departing power tracks or power plane.

If it died purely on ripple current, you'd expect its neighbors to be showing signs of that too.

But when everything is a blackened mess like that, it's pretty hard to see everything. Either that black is PCB charring, or it's chemical attack from whatever passed as a liquid in the cap. Charred PCB might be more brownish than black tar colored.

The pattern suggests it may have vented, down low. Like maybe a hole burned in the cap, or the seal on the bottom releasing under pressure.

Paul

Yes, the current in those cards is absurd. Hence the use of 12V instead of the 1V for the GPU chip. Maybe they should switch to something higher than 12V?

Do they show gradual signs or just a sudden pop?

There was a very strong smell of TCP (normally a disinfectant) when it did it. The area next to it is a copper track, now no longer attached to the board, about 1cm squared which has no sign of blue paint left above it. I assume the paint burnt off.

Not sure where all the carbon came from. Under the capacitor are only minor signs much came out the bottom.

That could be a +5V shorted to +12V fault. I could see that blowing all the +5V logic.

Paul

When you're doing this, you can share a big supply across multiple cards.

The OPs setup is not neat and tidy like that.

Paul

I have a crypto currency customer that has one of these. A super computer using the GPU's as parallel processors. The CPU does hardly anything.

There's no evidence that the cap was the first part to fail, or by what means.

The flammability of these parts or their contents can't be considered as anything better than 'will not sustain open flame' - but they'll burn if subjected to sufficient temperature and energy, as will FR4 printed wiring.

RL

Must be better than 70s stuff, I had a stereo amp catch fire inside, and it sustained the flame for 20 seconds before I blew it out.

Just from water? That's hard to believe.

That's hard to believe for sure. I wash my desktop's motherboard with water every 12 months and there is no malfunction after cleaning and drying it throughly. Machine is still as fast as it was when I bought it 5 years ago.

It worked for my stereo. I guess if water conducts a bit in one part of the circuit, everything goes out of whack.

Why on earth would you do that? Only time I've heard of water on a motherboard was when my water cooling burst, and someone who got drunk and spilt food on one.

OK. That leaves overstressed, cheap, and fundamentally useless.

No, because I run them at the designed clock speed and keep them well within their temperature limit.

They're quality cards, just older. The price of new cards is absurd.

What on earth makes you say that?