Miyano KNC45 Spindle Speed Issue Frenic 5000 V2

[Whitecat812]

Our Miyano KNC45 spindle stopped responding to spped commands. If you turn it on manually, it turns at about 50rpm but with a "for lack of a better word" warble. the speed fluctuates between 45-50 and you can hear a high pitched sound that changes with the "warble"
We had a company tell us it was the drive(Frenic 5000V2) and we sent it out for repair. They benched it and it worked on their bench. After reinstalling it we have the same issue....it won't turn faster than 45-50 rpm whether manually or programming a speed. The parameters haven't changed compared to the printout we have. Any idea what could be causing this spindle rpm issue?
Thanks

[SGARCIAM]

Our Miyano KNC45 spindle stopped responding to spped commands. If you turn it on manually, it turns at about 50rpm but with a "for lack of a better word" warble. the speed fluctuates between 45-50 and you can hear a high pitched sound that changes with the "warble" We had a company tell us it was the drive(Frenic 5000V2) and we sent it out for repair. They benched it and it worked on their bench. After reinstalling it we have the same issue....it won't turn faster than 45-50 rpm whether manually or programming a speed. The parameters haven't changed compared to the printout we have. Any idea what could be causing this spindle rpm issue?Thanks

Do you have the Electrical manual for this machine ?sgarciam2@yahoo.com