Dave wrote:
what does the voltage read when it is turned on? an rs-20a is probably not
so old that caps would go bad, and the low voltage left over when you turn
it off probably means the caps are holding a charge.

Or if anything is externally connected to the power
supply, the left over low voltage can be coming from
that connected device. I have my RS-20 connected to
a deep discharge marine battery. If I forget to
disconnect the battery from the power supply when
I power down the supply, the meter on the supply
displays the battery voltage. I'm told that can
damage the regulator within the supply but that
has never happened to me.
--
73, Cecil http://www.w5dxp.com