text: <s>[INST] Electrical buzz noise from Allen_Bradelly servo motor MPM-B2153F-SJ72AA Dear all; Recently I have met a very strange and tough problem from servo motor MPM-B2153F-SJ72AA, that is , one of servo motors(MPM-B2153F-SJ72AA) is out of speed control for many times during the running period and can produce electrical buzz noise from the motor after enable the motor, the motor speed is not very stable when you rotate it as a specific speed in manual . and the Kinetix 6000 driver has not any fault codes display, is only for 4 . Each time we just powered cycle the mains or removed the encoder cable plug and then mounted it again , the motor 's buzz noise was lost and the control restore normal . this problem often occurred irregularly. we have done the following actions ,but finally the problem is still existed. 1. replaced the kinetix 6000 driver for this motor 2. replaced the power cable and encoder cable for this motor 3. replaced the mains power for this driver ; 4. swapped the back rail for this driver 5. swapped the motors with the other good motor 6. swapped the plc control program with the other product line Now we don't know which condition cause the motor buzz noise? Does anyone have this experience! we are very puzzled about this problem, do you have some good idea about it ? Thanks Jason [/INST] #1 - Have you tried re-tuning the axis? Specifically, have you tried decreasing the gains? Just because the axis can be auto-tuned doesn't mean the resulting gains are good for the application. #2 - Verify the power wiring at the drive. Getting two phases mixed up can make for some rather interesting motor movement. While you have changed the motor power cable, doing an exact conductor swap will not prove anything if the phases were mixed up to begin with. \\n </s>