100000000 times THANK YOU ARC Tech-109!
The M3a is now functional thanks to you!
Granted it is in dire need of a tube alignment and white balance (and a better capture card), it works!
As I suspected, the PR-61 board on mine was faulty as well as the IE-7 board.
Had to have every flashlight and lamp pointed at the subject, but I expect that from a tube camera.