[MrFixr55]

@ Morzh, yeah, time marches on.

I still remember when the IBM clones came out and the sales jingle for Kaypro advertzing that they came with 2 disk drives, 64K of ram and a green screen monitor for only $1595. $1595 buys what? An Intel I7, 16GB of RAM, a 1TB solid state hard drive, touch screen and Windows 11 PRo or Enterprise. All in a laptop.

[morzh]

There are many things to consider when pondering the working voltage vs capacitance.
Not only it is different between the wet lytics and other caps, it is different between the types, manufacturers and older/newer types.

If the voltage is lower, the oxide layer which is the dielectric, will grow. When it grows, it will reduce the capacitance.
However if the voltage is much smaller than the WV, the oxide will stop forming properly and will start eroding, forming pits. But the capacitance might grow.
So, if you subject it to high voltage (or after the long storage) without re-forming, the cap might fail. If reformed, these pits and thinned oxide usually heal.
However, I do not think that using a 450V cap in 250V circuit will adversely affect anything.

[Arran]

Mike;
The photoflash caps I was using were mostly Rubicon brand, and I typically reform them before using on a resistance capacitance bridge. I'm guessing that the modern electrolytes, especially in photoflash caps, must work differently then the types they were using in sets in the 1949s and 50s, maybe it doesn't put as much of a load across the rectifier cathode for as long as an Aerovox one would have back in the day?
Regards
Arran

[morzh]

Well, if you remember the Capacitor Plague of the end of 1990s and beginning of 2000s, the electrolyte was the reason.

Rubicon developed the water-based electrolyte, which was much cheaper. And provided for much lower ESR.
This was important for hi-ripple/low ESR caps, that were lower voltages (below 100V) and were used mostly as the output filters in switching power supplies.
So the recipe was stolen, but the proprietary stabilizers Rubicon used were overlooked.

So, yes, today's electrolytes are different and in those Low ESR lower voltage caps they are aqueous.
The other electrolytes are different also from the old ones.

[MrFixr55]

I believe that load was related to capacitance, not the type of electrolytes. EE types please chime in.

We had a big problem with a particular company that was building and supplying OEM towers for us where the electrolytic caps would be bad. However, this may have been around 2005 for us.

[klondike98]

Well, the 450v 40uF cap is going to stay in there until the next guy goes into to fix it but I will keep that in mind for the future. I did get it all back together and will say that the most difficult part of the entire restoration is remounting the clock inside the cabinet. I had to mount the clock from the front, hold it in place using various rigged up braces, solder in the power leads, then connect the clock to the aluminum back of the clock while needing four hands but not really being able to see to put the two mounting screws in place.

   

Thanks for all the advice and comments! Its always fun to clean these up and make them play again. On to the next one....