Help! Buffer takes off at full speed

[Goodloe3]

Hey autogeeks. Got a problem . . .
While buffing, after a my rotary buffer takes off at full speed even thought it is set on 2 or 3. Any of you ever encounter this? Is it the brushes or something like that? After it cools down, it goes back to normal until it gets hot again. Then pull the trigger and it runs wide open again.

Any ideas?
It's a Hitachi. Light, powerful. It's been a great machine until recently. And please no replies telling me how great your Flex or Makita buffers are. I know they are super machines, just can't afford one right now.

Thanks guys.

[BobbyG]

There's something wrong with the electronics or the switch or possibly both. Since it's related to heat it really points to something electrical and not mechanical. Possibly take it to a repair shop?

I know this isn't much help but there's not much else you can do....

[Kevin Cullen]

Brushes should not make it go full speed. When brushes wear out they usually give sign like eratic stop,start operations. I agree with Bobby that it could be the electronic speed control. Electronics are very heat sensitive. Myself, I would take it apart and look for any loose wires or signs of heat.