Yeah, I know its a rotation of the "AC Output Reconnection Switch"...I have 3 MEP-002a's if you look at my signature. Have you downloaded all the MEP-002a manuals and followed the troubleshooting guide?
The contacts on that switch are known to become intermittent with age. I would switch it back and forth several times to exercise the contacts on the wafers between the switch contacts since this happened after switching it.
There are several threads that if you search "MEP-002a MEP-003a voltage high VR" or similar terms...you will get several hits for threads where this has happened. Causes range from the switch itself, the 2 rectangular potentiometers on the AC Voltage Regulation Board, the VR board itself (output transistors) transformers, grounding, etc.
Since you have multiple MEP-002a units, if you are in a position to take one down and swap out known good parts it might help expedite your troubleshooting process. Swapping out the AC VR is easy and would eliminate that as a problem, but I would follow the TM trouble shooting guide order first.
Edit: Here is a
good thread that is describing similar problems to what you are experiencing and the troubleshooting that was performed.