Technical question: Do certain electronic components, e.g. capacitors, need to "form" before they operate at their best?
Electrolytic caps do need to form and the form time is related to how long they have been off or stored. This is why smart tech bring up old equipment on a variac, to let the caps form. If power caps are just hit with full voltage they will draw DC leakage current as they form. If they get too hot in the process they explode. The process is regenerative so it goes very fast at the end. Many people destroy otherwise good caps by just turning things on for too long.
If people want to know there is a lot to be said about these caps and I have studied them in depth. I made a current limited "former" that will prevent the overheating runaway. Sometimes old caps are better than what is being made now. I know because Ive tested them.
It takes about a day to fully form a 10 year old cap. They often form to much higher voltage than the rating. The old man at Mallory explained it all to me. In large quantities where we spec what we want, the voltage written on the cap is more often the voltage on the purchase order rather than what the cap was made for.
For example we ordered 1000 pcs of 150 uf 315 volt caps at Beveridge. I tested them and found them good to over 500 volts, therefore I would say they could have been marked 450 but we ordered 315V. We got more than we paid for, but one has to TEST these things to know.
He also told me that stored at cool temperatures 10 years takes only a month off the life of a cap. Basically nothing. Its all about the water inside staying inside.
I am sad to report that modern caps from good makers are having other problems that prevent this kind of testing. Recently I found some good caps flashed over at slightly above rating because the edge margins on the paper had been reduced to shrink the cap's size. Now that is sad.
My advice, heed this well, If you have old lytics that are working fine, DO NOT REPLACE THEM. The new ones may not last nearly as long. I have 30 year old caps in RM-9s that are doing just fine. I don't think modern caps are going to last 30 years.
Oh, perhaps I forgot to mention, Im really into finding out why parts fail. One has to care to make long lasting equipment.