Something is wiring with the seped control. Start from the speed sensor on the motor - often a pickup on the end of the shaft. The control box sees no speed signal frm the motor and assumes it isn't turning, so it cranks up the juice a bit. Rinse and repeat till the motor is going at full chat.
It may even be that the thing the speed sensor senses has come unscrewed from the end of the motor shaft and fallen off - that DID happen to me once; I found it in th edust under the machine, screwed it back in with a smear of Evostik on the thread (Only thing I had at the time). I can't remember the make of machine.
The other possibiity is that the control box isn't sensing the speed signal - more expensive to replace.
Check for speed sensors, busted/shorted wires especially round the motor and the like
acp, July 2017
