Also, the three caps at the bottom right may look like they are paralleled over the brushes, to reduce electrical/RF noise from the brushes+sliprings. Just guessing here, maybe you can confirm.
I hadn't yet thought about the fact that brushes may need a cap paralleled over them, but it does make sense.
(how 'bout drawing us a nice schematic, being the reverse engineer you are
(just teasing!))
Peter.