"He who marches out of step hears another drum." ~ Ken Kesey
We have had to replace a few things on our MSP3140, wiring / iron threads that wire the bulb to the units electronics. It could be starting to go somewhere and not supplying the proper electricity anymore. Ours actually gave off a bit of a burning smell just before going and we had to replace the special metal screw that carries the current through it to the bulb.It's not going to get better before it gets worse so call M&R and see what you need.
Thanks guys.Yes it is a newer unit 2010 I think.Like I said its a random thing that has not gotten any worse but would like to solve the issue.The unit is spotless inside and out, vents clear, fans working. I have not checked the taps but will later this week. The voltage is a little low in the shop, 108-111 vac. Our old shop had a pure 120-125 vac and never had trouble there.