The EP-38 series power supply has a semi-fatal design flaw: The transmitter high 
voltage bleeders are carbon resistors, are undersized and poorly ventilated. The 
trapped heat chars and burns a hole in the circuit board over time (many years). 
Also the resistors sooner or later age, crack and the exposed carbon can (and 
usually does) catch fire from the heat. The flames then completely destroy the 
circuit board (no longer available as a spare part). If you have one of these 
supplies in service I suggest that you immediately (like this coming weekend) 
replace the resistors with a higher wattage ceramic (i.e. flameproof) replacement 
and stand them off the board an inch or so for convection cooling. Note that the 
resistor leads carry high voltage and you will want to use sleeving over them.

A second, less critical flaw is that the PTT relays wear out and they are also 
No Longer Available. I've replaced them with a pair of octal plug-in KRP series 
relays. Simply remove the old relays and mount a piece of sheet metal over the 
holes and punch two octal socket size holes in the new metal then mount and wire 
the sockets of the new relays to match. Plug in two new relays and the supply is 
good for another 10-15 years, and at that time (if it's still in service) new 
replacement relays can simply be plugged in.