Or doesn’t.
It actually belongs to my father-in-law and he’s had it many years. He even tried to throw it out once, before I recovered it, fixed it, mended the cable he’d cut off and started using it again. A while back however, it started playing up once again.
When I took it apart this time I initially thought that there must be a broken wire, but I later discovered that it was the actual power switch that wasn’t working, in that applying power to the centre pins of the switch didn’t result in a voltage appearing on any of the outer pins.
It’s a double pole switch because the vacuum has a power outlet. In “normal” mode the vacuum just switches on. In the other mode it comes on when power is drawn from the power outlet, so I can have it come on when I start the chopsaw for instance.
I thought I’d pull the switch apart and have a look inside to see what was going on. Mostly what as going on was that it had filled up with sawdust 🙁 Obviously this isn’t great from the point of view of operating the switch, but it’s not great from a safety point of view either: sawdust in the presence of a spark has all sorts of opportunities not to end well.
The obvious place that sawdust might be getting in is around the ends of the switch rocker, so I think I’m going to reassemble the vacuum and fix some clear polythene over the top of the switch with insulting tape so the dust is kept out.