In article ,
"Tom Miller" wrote:

I think I just answered my own question. The hottest power supply is 30
years old and the other is 20. Both appear to meet their electrical
specifications.

Fred

Do they really meet their Specs?
Back then (30 years ago) the nominal in USA was more likely 110 volts
whereas today to follow Harmonisation rules it should be 120 which is a
like 9% increase. Of course there is a wide margin but you may be on the
high side. Just a thought.

Sounds like an Astron AS20 or similar. The transformers are made with cost
in mind and they do run hot even at no load.

The hotter one is a Kenwood KPS-21. However the insides are almost
identical to an Astron RS-20A, except the Kenwood does not have a
crowbar circuit installed. Date Codes on components are from 1980, and
I purchased it about 1981. Its label says input voltage should be 120
VAC

The other is an Astron RS-20A with date codes from the mid-1990s. Its
label says input voltage should be 115 VAC. It was recently purchased
from an estate with a goal of replacing the hot KPS-21!

Line voltage here runs about 119 VAC, although equipment should be
designed to operate over a +/- ten percent range (108 to 132 VAC) in the
U.S.

Fred