What do old electrolytic capacitors smell like? - Page 1
Forum section: electronics / beginners

author: smbaker
author_rank: Regular Contributor
timestamp: November 03, 2015, 12:22:07 am
content: I was going through boxes in the garage last week, and I have this plastic container of miscellaneous stuff that I bought on ebay about 15 years ago. It's been sealed for that time. Pretty good seal, though probably not air tight.Upon opening the lid, I'm assaulted by an overwhelming odor that's somewhere between urine and dead animal. Visible in the container, among other things, are four large (2" diameter, 6" tall, blue, with screw terminals on the top) electrolytics. Probably NOS from the 80s. Are those what's stinking up the container so badly? Or did a mouse go MIA 15 years ago?I'm too scared to open it up and find out for sure what it is. Maybe if I had some hazmat gear. Or an exorcist. Something.

author: Rick Law
author_rank: Super Contributor
timestamp: November 03, 2015, 12:38:31 am
content: Smell is hard to put into words. If you have a spare capacitor, you can always "cook" one to see how it smells.I learn that smell when I mistakenly put 30V into a 10V capacitor. I did not do that intentionally. If you are to do that internationally, take all safety measures and make sure you use a power source with current limit.

author: GreyWoolfe
author_rank: Unknown
timestamp: November 03, 2015, 01:08:29 am
content: I have heard that blown caps smell like fish or cat pee. I do know for sure, but I do know that SWMBO has been pissed when I have popped a cap in the past. That's good enough for me. The smell is truly unique and unforgettable.

author: Ian.M
author_rank: Super Contributor
timestamp: November 03, 2015, 01:20:29 am
content: So tip it out on an old newspaper on the drive and if its got mummified vermin, and the stuff cant be or isn't worth decontaminating with neat bleach, bin-bag it!Mind you, that vintage caps smelled pretty sick if you blew them, even when brand new

author: bills
author_rank: Frequent Contributor
timestamp: November 03, 2015, 01:45:30 am
content: It's easy to tell if old caps are still good, when you throw them in the trash can if they make a sound they are bad.

author: rickselectricalprojects
author_rank: Regular Contributor
timestamp: November 03, 2015, 02:03:48 am
content: bad... very, very bad.

author: AF6LJ
author_rank: Unknown
timestamp: November 03, 2015, 02:08:29 am
content: Quote from: smbaker on November 03, 2015, 12:22:07 amThat is an apt description...Add a few drops of male cat urine and you have it...

author: bills
author_rank: Frequent Contributor
timestamp: November 03, 2015, 02:50:07 am
content: Quote from: rickselectricalprojects on November 03, 2015, 02:03:48 amI know it sounds bad, But I work on and restore a lot of vintage equipment and when one of these old caps short out and destroy an unreplaceable part than what.I would rather them make a clunk when they hit the trash can (recycle bin) than ruin something. most caps are cheap why take a chance. (reforming doesn't work 90% of the time) If they are over 5 years old they should be checked very carefully, any older toss them.

author: Cliff Matthews
author_rank: Unknown
timestamp: November 03, 2015, 02:51:41 am
content: I've had clear plastic coated silver cap's that, when shaken, had a thud sound inside. Curious as ever, I opened one to find it mostly dried-out. If in doubt, "Smash it! Hit it with a hammer and trash it!" Sonny Bono, cira 1970's on Luv Boat. (yeah I know, kinda sounds sick now..)

author: bills
author_rank: Frequent Contributor
timestamp: November 03, 2015, 02:59:56 am
content: there are of course exceptions to what I posted, I have worked with high quality equipment that have been in service for 20+years and are still working fine. But that is the exception rather than the rule.Let the flames begin.

author: coppice
author_rank: Super Contributor
timestamp: November 03, 2015, 08:02:59 am
content: 60s and early 70s electrolytics tend to smell of poo when opened. If one explodes you find the contents have a matching brown colour. Newer ones tend to smell more like rotting fish, so presumably amines are released by whatever witch's potion is in them. The inside are much paler in colour, too.

author: Electric flower
author_rank: Regular Contributor
timestamp: November 03, 2015, 08:56:18 pm
content: Long time ago I was dissasembleing electrolytic caps just for kicks and curiosity and it were some used caps from 90s TVs, mostly powersupplies and it smelled like sugary piss mixed with acetone (70/30 ratio to be exact), and if you get it on your hands it doesen't just wash away with water...

author: mzzj
author_rank: Super Contributor
timestamp: November 03, 2015, 11:25:56 pm
content: Quote from: Electric flower on November 03, 2015, 08:56:18 pmPretty desciptive, but I am not going to verify the ratio myself

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: November 04, 2015, 11:02:59 am
content: When I started work in an R&D lab (1974) we used to connect 6,800uF 25V electrolytics to a variac with a diode and crank it up with the cap hanging over the window ledge- the bang was impressive, as was the stink and miasma. The building site opposite was kept amused by these japes.Older and wiser BT.

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: November 04, 2015, 01:35:02 pm
content: Quote from: smbaker on November 03, 2015, 12:22:07 amDon't be scared. Be curious. Open it and you will know.

author: Ian.M
author_rank: Super Contributor
timestamp: November 04, 2015, 01:55:31 pm
content: +1It cant be significantly worse than finding last week's dog turd in a little baggie on a hot day the hard way! Just do it outside and let it 'breathe' for a while before tipping it out.