The funnel was cracked on my game when I first got it. It eventually became broken. Replaced it and now many years and probably over 1000 games later it is still fine.
As for DTR, I've opted for leaving it set on two ball. Works like it is intended to. However, if I ever get two balls stuck in the ring(rarely) I have to immediately reach down and turn the game off, otherwise it will blow the fuse.