I work in a computer repair shop, but we're known for having a go at most electronics in general.
A customer walked in, clutching an external hard drive. He handed it over the counter to me along with the power cable and usb cable. and told me he can't get it to fire up. No big deal, I think, I ask him what it does when he tries, and he says "Nothing, it just wont load on my PC". So I went ahead and plugged it in, hit the power switch.
Straight away this horrible smelling smoke started to come out the vents, and sparks fly out where the power button is. coughing and spluttering, I unplug it and look at him.
He says "Oh it did that when i tried it too".