This isn't related to a rotary machine but at a coil (micky bee) machine i own.
What's happening is that voltage rising and dropping, so.... i have replaced everything but the frame and rebuilt it exactly to how it was originally bought, brand new, and with good quality parts, plus i changed the clip cord and the foot switch but the problem still persists.
I use a copy of the critical power supply (hurricane) and wondered if this could be the problem, however all my other machines run sweet, both rotary's and coils.

Any ideas would be great as this one seems to have me rather confused.

?????