Barry Irby
I thought I had the same condition John was talking about, a failed pressure switch. the little "unloader" valve that bleeds off the pressure indie the compressor so it won't have to try to start against a head of pressure. You can hear them go Psst as the unit stops, unless they fail and then they go PPPPSSSSSSS.....

The failed tank has a pin hole, I felt it leaking. It lives in a outdoor closet behind the shop, so if it failed it would be interesting and possibly exciting, but probably not dangerous.

I am torn between just letting it go and having a friend fix it and save it as a spare.

I have a new Dewalt unit that sits on top of a 30 gallon tank that I bought at an auction. Doesn't look as sturdy as the old one but may last me the rest of my life.