Servo Oscillation Issue at ±6.6V 5i25 + 7i77, Analog Control

What division do you propose, I tried the lowest 625 per mm.

Does the division change the point at which you get oscillations?

Did you check that the  7i77s 5V is stable?

625 counts per mm is certainly low enough ( < 100 KHz count rate at 8.3 M/min ) 

 

I haven't checked, but today I will check the only thing I tried to power the 7i77 with a separate power supply but it didn't help.