[jclark003]

Have you checked the isolation transformer to see if it is operational and passing power to the MC? You should hear the internal contactors throw 10 seconds after you plug in the 50a service. Pretty noticeable thunk.

If the isolation transformer is working then the light not illuminating isn’t a positive sign as it could indicate that the internal PC board has failed. The board senses power from the different sources and then energizes a series of contactors to send power out two buses that feed your AC panel. The contactors can still be purchased but if the PC board failed there is none to be found. I would still try the override switch