[TenTec] Orion II remaining powered after power switch in upper left corner has been turned OFF

[Leon]

On my Orion II lately when I turn the power switch off, the radio 
remains on.  The switch is not the culprit as I changed it out.
It's as though a relay or delay circuit is over-riding the OFF condition 
of the power switch.  Eventually it will turn itself off. Thanks for any 
suggestions
relative to the cause of the problem and how I I might resolve it.

Leon Pringle   W5NA