[Elecraft] KPA500 power supply

[Hank P]

Since we are in monsoon season here in AZ - if any storm is in area or 
predicted - I  disconnect everything - both at tower and at shack wall.

I noticed this morning that when I plug the KPA500 back in -(its on a 240 
circuit all by itself)  I hear what appears to be an initial  transformer 
magnetizing input hum even though the ON switch is OFF .

All seems to be working fine - going  from ON to OFF the fan runs to bleed 
down the PS and amp works  OK - I just never noticed this hum before .And 
the hum is just at the initial  plug in - it does out to inaudible.

It appears even when the KPA500 is "OFF"  the transformers are still being 
fed from AC line  - TRUE ????

Sheet 1 of 2 of the PS shows a "switch" right at input but that appears to 
be part of the input 120/240  module , KPA500 Front Panel Switches shows the 
"ON-OFF" sw just as a closure to ground feeding control logic at which point 
I get crosseyed.

Hank K7HP