Exploding cap

[Wounded Paw]

This is the board from a Rebote 2.5 I built for my guitar player.  Someone in his other band plugged it into the wrong adaptor, not sure what the voltage was but it was enough to make the 47uF capacitor going to ground from the +9v line explode.  It also took out the TL072 IC.  It's hard to see in the picture but half the IC is actually gone.

[bancika]

next time put polarity protection diode

[BRingoC]

That blew up... that blew up real good too.

[Wounded Paw]

replaced the cap and both ICs but no delay signal, only clean coming through.  Where should I look first or should I scrap it and start over?

[jlullo]

don't scrap it yet!  how is your voltage regulator looking?

here's a post OldRocker helped me with regarding where on the PT2399 the repeats should be coming from:
http://www.diystompboxes.com/smfforum/index.php?topic=61010.msg479057#msg479057

mine was i reference to the Rebote 2, not the 2.5, but it should be the same on the chip!  you'll also need to build an audio probe if you haven't yet

[Wounded Paw]

yep, it's the voltage regulator.  Don't have a spare but I'll grab one tomorrow.

[s.r.v.]

  i didnt think caps actually exploded. i thought they just like popped and died. lol i found this pretty funny

[sshrugg]

  Whoaaaah!  Thanks for sharing that pic!  Good luck troubleshooting.

[jlullo]

WP,
great!  that's awesome for you... an easy fix!

and oh yes, caps EXPLODE!  my friend bought a beard trimmer, and the first day he was charging it, one of the caps exploded in the adapter and left a charred black mark on his wall

[Plinky]

i didnt think caps actually exploded. i thought they just like popped and died. lol i found this pretty funny

And if you didn't see it explode, you'll know it did by the lovely aroma they emit.

[deathbringer07]

kind of looks like a bird just pooped in ur pcb.....

[axg20202]

I did something similar the other day, except I was actually touching the cap when it exploded (to confirm that it was connected the wrong way round and was getting hot) - no real harm done....just call me black finger....

[birt]

it gets interesting when a big cap explodes tough. you don't want to be too close when that happens. and you also don't want to clean up teh mess if it doesn't pop inside an enclosure

[oldschoolanalog]

...and oh yes, caps EXPLODE! 

You should see the carnage when a 100uf Tantalum explodes...
I'm almost tempted to blow one up on purpose for "demonstration purposes", and post a pic.
Too expensive though.
IMHO, not having some sort of polarity protection (pick one) is tempting fate.

[sshrugg]

I did something similar the other day, except I was actually touching the cap when it exploded (to confirm that it was connected the wrong way round and was getting hot) - no real harm done....just call me black finger....

haha!  I did the same thing with an LED.  Freaked me out.

[axg20202]

Me too. Made one hell of a bang and for a moment I thought I'd lost a finger!     I like to give the neighbours a laugh now and then by providing a loud bang in my shed workshop, immediately followed by a shouted expletive. Still, at least the wife didn't have to loosen my death grip on some electrical device using a broomstick (i've been playing with AC lately). 

[Fuzzy-Train]

Would've loved to see a high speed vid of that thing blowing up. 

Luckily I haven't blow anything up yet. *crosses fingers...knocks on wood* Double protection baby!

[Alex C]

No high speed, but here are a few videos I found just by searching "exploding capacitor" on Youtube.  There are lots more, and probably better ones; these are just the first few that I saw:
http://www.youtube.com/watch?v=ToWsF3HcQUU
http://www.youtube.com/watch?v=8-A0kXP7jD4
http://www.youtube.com/watch?v=akCI_Hm9iE0

[jaytee]

Nice 

[spud]

Talk about toxic fumes   - hope they had a vent system or at least an open window, yuck.  I would imagine those things have PCBs in them, or are they "compliant" - is that just for lead or does it cover "toxic goo" as well?