[PhilBot]

I finaly stumbled across the reason for my noisy drive train.

The problem ended up being caused by noisy throttle inputs on the OI.
The noise that was being seen by the OI was bouncing the motor speed in and out of the deadband of the Victor when a slow speed was being requested.

My joystick deadband logic may have been part of the problem...

I first check to see if the input is outside the deadband, and if so,I subtract the deadband from the current reading. This then gives me a speed signal that is continous all the way to zero.

Unfortunately, this also makes the output to the victor continous from zero up, so any noise on the joystick can bounce the victor in and out of it's minimal activation signal, thus causing the motor to start and stop based on the joystick noise. This rapid on-off action was being transmitted into the gearbox and causing all sorts of ugly noises.

Rather than re-offsetting the levels, and possibly changing the other characteristics of the signal, I now just pass the joystick requests through a FIR filter (like oversampling the RC inputs), and so the victor doesn't see the noise. Suddenly I have a MUCH quieter drive system.... YAY...

Phil.