No Joe that's definitely not the buffer...Lol

It looks very much like a noise issue.? But knowing your setup and the fact spindle isn't running I'd be surprised if it was.! . . . . Have you grounded the chassis.?

I'd be going over all the wire connections in the control box first looking for loose connections or stray wires. Also If you have any plug connections like DIN sockets on motor cables I'd check them out as well, in fact, chop them off and throw them in the bin as they are a pain in the arse.!!