electrolytic caps blew up !!!

Way back in junior high electronics class, although it happened to my lab pardner. For some reason he hooked an electrolytic up to the bench DC supply and gradually cranked up the voltage till it blew. He had this perfect circle of little tiny bits of paper around him (and on him), and a very surprised look.

Sure, I've seen 'lytics blow up. The usual causes are:

Reverse polarity (connected backwards)

Overvoltage

Excessive ripple current (e.g., a shorted rectifier in a power supply).

The sound is in the Lytic!
:grin:
No danger. But those old PCB caps...lookout!
:twisted:

My noise module on my modular synth became an explosion module... after that I never look straight on the pcb while powering it up the first time.

used to blow em up in lab back in school :green:


120 strips that ran across the front of the lab tables.. we would plug in caps along the front and plug the strip in for some fun

oh and the tables were bolted to the floor...

why is this important?

well on one occassion I had some "welding cement" kinda like super glue but stronger... I crawled up behind this guys chair in front of me ( he was a bit heavy and scooted into the table) proceeded to glue his chair legs to the floor :green:

worked like a charm! his ass was stuck for awhile eventually the floor tiles broke and he got loose... I ran my ass off after that one haha

Above my bench at work, there is a dent in the ceiling tile from a cap can that blew out whilst testing an amp. (42V rails on 35V caps!) Whee!

Electrolyte will eat the solder mask and can then cause arcing. I think it can also eat the copper as well. Be sure to clean it off of any PCB.

Excessive ripple can also occur in ckts that have high current draw (Tens of Amps or more). Low ESR caps or more caps will usually solve the problem.

Peace!
Charlie

fluke meter? those are notorious for showing CrAzY readings when the batteries are just a little low...

Maybe just the leads are trashed?

Was the "Low Battery" Icon on?

HTH!
Charlie

[quote author="buttachunk"]

has this happened to anyone else ?[/quote]

Ohhh yes..I dont think that you are a real livin` EE, or DIY´er if this has not happend to you at least once...*GGG* Everybody I know who´s into Electrical stuff has tried this..

Kind regards

Peter

tant caps are great for small blasting operations, like getting your partner's tool box open after he steals your pliers one too many times...

and boy do they hurt when they go off in the palm of your hand too. i had a bruise on the Palm of my hand for a week after a SMALL one went off. sounded like a small gunshot!

is it true digital? I bet the A/D converter is dead

[quote author="buttachunk"]...my multimeter is completely broken...[/quote]So, what blew the caps? Were you putting more voltage across them than you thought you were?

How's this for a capacitor explosion: 3600uF, 450 volt capacitors - a dozen of them. They were used in a motor drive and the power supply (power factor corrector) went a bit nuts. The capacitors released their contents with authority.

saw something similar, a 3000ufd 450 motor starter(size of coke can) blow up after the motor locked a big BZZZZZZZ and weeeeeeeeeeee! smelly electrolyte oil everywhere.. what a stink.

I've seen a few blow, but never blown one myself (knock on wood!). Never the less, I always put a decent sized cardboard box over my supplies when powering them on for the first time, just in case.

My new at the time Studer 827 was acting up. In the process of troubleshooting I sent a big 'lytic accross the control room. Like a rocket, trail of smoke. It hit a window 15 feet away and left a mark like a pebble on a windshield. Later that day I found out that Studer had recently been sold to Harmon and their Nashville tech department couldn't care less about my problems since they already had my money. I sent them the whole suspect card and was left without an 827. They fixed and returned the card before the end of the week.