[Elecraft] RS 22-507 Power Supply

[Augie Hansen]

I have been using a Radio Shack switching power supply (part number RS 
22-507), which is a 13.8 volt, 3 amp supply both to power my K2 and to 
power a test setup for a microcontroller project. The output is clean 
and stable when the unit is powered on.

However, the supply is exhibiting a strange behavior when the unit is 
turned off. It puts out a short full-voltage pulse (~0.2 second) at 
intervals of several minutes. These pulses occur  whether the supply is 
connected to a load or not. It is not related to anything on the AC 
input side. The same behavior was seen at a temporary lab I set up in 
Rhode Island and here in my lab in Denver.

I wonder if any of you have had a similar experience with this model or 
any other switching supply. If so, please let me know.

73,
Gus Hansen
KB0YH