Caps installed backwards

If you watch the bottom of the blue capacitor at 3:35 or so, you will see the characteristic "bulge" that is typical of these caps failing. That is why you need to check the bottoms as well as the tops (newer caps typically have pressure relief lines cut into the tops so they vent without popping) when doing a recap of any circuit. If there is a bulge, definitely replace it.

ken
 
Also, if there's a small crack, replace them. Sometimes they don't bulge but you'll see a crack and maybe some gunk oozing out the top.

Just don't mistake the glue they use on some caps for gunk leaking out. They are 2 very different things.
 
I didn't see it happen, but a friend of mine was wiring a circuit on a model railroad, and installed a huge ass cap. Not sure if he had it in backwards or what, but when powered up, it popped, and sounded like a gunshot going off (and lots of smoke for good measure) Scared the crap out of everyone there ;)
 
What's almost alarming is how the dipped cap flamed up! I'm almost curious what a pcb would look like wired backwards. Prob not as catastrophic but someone should do this, then go mythbusters and make sure it happens :)
 
I'd be interested in seeing a big-blue wired to 220v DC backwards...

Fixed another part... No backwards on AC, just 'out of phase'. ;)

The worst part about popped caps like those are the rotten fish smell! YUCK.
 
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