The problem was apparently caused by a lack of ground in the system.
These power supplies have a RF protection capacitor that feed voltage to ground.
Take away the ground and there is voltage on the case , ground yourself and you become part of the circuit.
This voltage will not likely kill you but will give you quite a tingle.
Such voltages are considered dangerous and are to be avoided,
So prevention, always connect to a properly grounded outlet. I have an old house so some of the outlets are not grounded.
Never use a cheater plug you know those things that allow a three pong plug to plug into a two prong extension.
Get an outlet tester and use it. They are like $ 5 us at the local big box home center.
So STAY GROUNDED.
For those of you who have never seen an outlet tester I included a picture.
Safety first .
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