Life span of selenium rectifiers?

[jr_tech]

I have several late 40s portable radios that work fine with their original selenium rectifiers. When I restore one of these sets, I usually just check the voltage output of the rectifier, and if it is up to spec, I leave it alone.

Some that needed to be replaced may have been damaged by failure of a part downstream, such as a filter cap short.

These radios are not "daily drivers" however, but I would like for them to work if I turn them on for a demo.

If you use those Zeniths a lot, it might be a good idea to replace the selenium rectifier... it could fail tomorrow, or in 50 years! No way to really predict. Mushy, weak audio could be a clue that the rectifier output is dropping...measure that B+ voltage!... As the output drops, the rectifier will run hotter, and heat will accelerate failure!

jr