Mystery 80s Sanyo cap - perhaps polymer?

[cj_reha]

Hey all I've been working on a 1984 Sanyo 27" color TV which had a smattering of bad caps in the video switching circuit. I found this oddball little 1uF 25V cap which looks to me like an early polymer, but I can't find concrete info proving it. I know Sanyo was a big player in early polymer cap development and this is the time period where they were just getting on the market, so I'm wondering if anyone has crusty old datasheets that could help identify it and determine if my suspicions are right? It has the same epoxy end seal and font/formatting as some old stock Os-Cons I've got laying around, and compared to one of the conventional looking electrolytics I also changed out, the ESR tests much better (2.4 ohms vs. nearly 5 for the black lytic).

Is this a really early polymer, or just a weird looking electrolytic? I'm more curious than anything - the set works fine with a standard electrolytic in its place. I simply have a fascination with early/oddball cap history and would love to learn more about Sanyo's offerings since information on them seems harder to come by over one of the more commonly seen brands like Nichicon or Panasonic. I've attached photos of all the markings on the cap and comparisons with other caps to hopefully help.

Thanks everyone

[stj]

Re: Mystery 80s Sanyo cap - perhaps polymer?

i think it's just an electrolytic with a sealed can.
some american company used to seal all their electrolytics with epoxy too - i used to see them in a lot of arcade gear from the 80's

[cj_reha]

Re: Mystery 80s Sanyo cap - perhaps polymer?

i think it's just an electrolytic with a sealed can.
some american company used to seal all their electrolytics with epoxy too - i used to see them in a lot of arcade gear from the 80's

Maybe you're thinking of Illinois Capacitor? I've seen some caps from them from that time period that have the same epoxy seal. Lots of Sprague caps from the 70s had bright red epoxy seals too - I see a lot of those at work in old minicomputer equipment. They're all junk now sadly...the tiny caps just don't hold up.

It's definitely possible they're plain ol lytics with a weird seal...I'm just curious to see if there's someone in the woodwork somewhere who worked on the design team or something and could say for sure. It's a long shot but curiosity has gotten the better of me

[stj]

Re: Mystery 80s Sanyo cap - perhaps polymer?

cut it open?

[R_J]

Re: Mystery 80s Sanyo cap - perhaps polymer?

Likely just a an electrolytic in a plastic mold vs an aluminum can

[redwire]

Re: Mystery 80s Sanyo cap - perhaps polymer?

That old Sanyo cap is electrolytic, oddly enough the same construction was used decades later in their polymer lineup.
In the '80's a few electrolytic capacitor manufacturers went with using hard epoxy instead of a rubber bung. Rubber is not great as a seal technology. Sangamo 301.
Epoxy didn't really work - I've seen cracked epoxy or the cap has dried out low value. I think the aluminum can thermal expansion, or hydrogen pressure just was more than epoxy could deal with. Although it could be internal corrosion. Take one apart.

So the industry settled on synthetic rubbers butadiene for the bung, they do much better.

[stj]

Re: Mystery 80s Sanyo cap - perhaps polymer?

i like the soviet ones - metal can, plastic bung and a rubber washer or o-ring in the crimp
they still dry up, but they dont leak around the legs!

[redwire]

Re: Mystery 80s Sanyo cap - perhaps polymer?

This explains all the unexploded missiles lol.
But it all comes down to material tech. Rubber dries out and shrinks, epoxy cracks, wax/tar dried out and shrank etc. etc.
Maybe the electrolyte attacks the seal or something. I think we're at the 100 year mark for electrolytic capacitors.