hey guys I was installing a dryer vent for my mom with my makita bhp 452 and a new 4" hole saw. one hole through a single jouist cleaning out the hole every little bit I can. my drill started smoking, I stopped using, then went back to it later, and it would not work. next day it operated fine for few mins then stopped working again, just pulling the trigger. so what could it be brushes or the whole armature? please help