Ok, the ones I was thinking of WEREN'T HPM ones. But guess what! The HPM one had decided it didn't want to turn off when I got home from work this morning. It wouldn't even turn off manually. I took it apart, the contacts didn't seem to be welded closed, so I'm not sure what the problem is. It looked like there's a flat metal bar that snaps back and forth to turn it on and off. That bit had shifted a little so that it wouldn't turn off again. I THINK that's it, assuming I didn't do that while disassembling it. Unfortunately, after reassembling it, it doesn't turn like it's supposed to so it's still busted.