Alex,
It sounds to me like a broken PS14. You might give Digitrax a call to see if this kind of failure-mode is a known problem.
If I found a PS14 behaving that way, I would probably choose to recycle it, and replace it with a new unit.
Of course, it is possible that your voltmeter is not reporting "real" data. Why do I say "real"? Because the PS14 is a high-efficiency _switching_ power supply. Your voltmeter _could_ be seeing some artifacts from that switching, and could therefore report a bogus value. I would be more suspicious of inexpensive, no-name meters than I would be of a major meter brand such as Fluke.
Regards,
Billybob
