620 problem

Hi Guys,

My Miggle 620 now seems to have a second way of controlling the board speed. All I have to do is move the switch/cord around and it will speed up or slow down. Plus it is making that high pitch vibrating sound that drives me nuts.

The thing is, I've only had the board three years. Is anyone else having performance issues with the 620 and how might I fix mine?

Thanks, Brian