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I've heard of magic smoke before, but...

T

Tiberian Fiend

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Mar 1, 2009
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Location
Central Florida
...I've never heard of magic shower of sparks! I plugged a Compaq VDU card that wouldn't work in my Deskpro into another computer to test it, and a capacitor exploded and sent fireworks across the room. You can see the trajectory the molten contents of the capacitor took in the photo below. Would this be worth trying to fix? What else might have been damaged by an event like this?

026.jpg
 
Ah, welcome to the world of tantalum capacitors! Be glad it wasn't one of these:

Axial-Tantalum-Capacitor.jpg

Those go off like little bombs! I've had /one/ go off, and now I always power up boards while not standing directly over them.

The good news is, other than the exploded capacitor, it's likely nothing was harmed. You can probably just leave the capacitor blown open and keep using the board. It'd be best to repair it, of course, and if you're handy with a soldering iron it should cost less than $5 (probably more like $1) to fix. Just read the value off of a similarly sized capacitor on the board and replace with the same.
 
Just make sure the capacitor didn't act as a fuse because something else in line was shorted to ground. Other then that just replace it and see what happens (after you clean it up).
 
Yep, I experienced the same thing for the first time on a 286 not to long ago. Quite impressive and scared the living daylights out of me.
 
Yep, I had this happen on a 286 motherboard - I had powered it off to fiddle with something, and I was peering over the board as I powered it on, and the tantalum cap shot up like a flare just centimetres from my face.
I learnt very quickly not to stick my face over computers as I turned them on after that :p

I replaced the blown cap with a new one, as well as all the other tantalum caps on there for good measure. Board still works fine.
 
Compgeke said:
Making a mental note: never stand in the way of a computer when turning it on.
Click to expand...

The caps can pop after the system's been on for some time. You just never can tell.

I maintain that there's nothing quite as lethal in caps as an old Sprague "Vitamin Q" steel-jacketed glass-sealed paper-in-oil capacitor. When those go, they shoot shrapnel.

Sprague-Vitamin-Q.jpg
 
Never had a Vitamin Q go on me, but I'd imagine it /is/ quite the boom! Fortunately, the hermetic tantalum I had go split open and remained one large piece of shrapnel.
 
I remember vividly working on an inverted chassis when one of those let loose. After I'd recovered my hearing, I noted a jagged corkscrew of steel hanging from ceiling. Just about 15 seconds before, I'd been probing around the cap with my meter...

I shut things down and poured myself a drink.
 
Everything will still work fine. Just replace the cap that blew.

I've had a power supply shoot smoke at me and four capacitors shoot (stuff) at me at the same time. You just never know what's around the corner.
 
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