My EX-21 is 4 1/2 yrs old and gets a lot of use( almost daily ) today the speed control went bonkers ...started running super fast and my control knob would not slow it down like it should have....I got the saw from Seyco and will call Ray when they open on Monday......My question to you folks is does this use a reostat or control that is a common item ....Has anyone had to replace one before and do you think it is something i can do myself .....The parts breakdown in the manual does not show the part....Just hoping one of you folks can shed some light.....Thanks Steve.