Need info on old Denon DJ media players to complete my database for class

I’m collecting data for a statistical project for grad school.

When you have the motor off on the original DN-S5000 and later 3700 and 3900, does the jog bend have a deadzone… a threshold you must rotate faster than, and are the negative and positive directions when bending with the platter when motor is off the same sensitivity?

I’m also interested in the SC2900’s jog bend behavior.

Thanks for your time.