Haha, college go brrr.

No progress has been made so far, BUT, I have two new developments:

1. I recently came across a far less-degraded copy of the original schematics. This should help clear up some of the confusion I've had in redrawing the schematics.
2. I may or may not have acquired a working Model 52, which is identical in all but the drive mechanism to the Model 51 that I intend to rebuild the logic board for. This should give me a good point of reference for what signals should look like.