How Do I Replace Mag 2 C Switch?

I have a favorite Mag 2 C [purple body] that I have a Diamond Lux III in, but the switch no longer works. I have opened the light up and removed the aluminum ring which has two ?pin-spanner? holes [is that what you call it]. The ring is about the size of a quarter. After that I can't see what to do next. The inside of the body of the light is threaded, and I've tried to twist the switch out, but it doesn't seem to want to budge. I imagine the switch extraction procedure will be similar to the Mag 2D or 3D.

Any help will be appreciated.

Thanks

On pre-1990 Mags like yours there are two steps. First, the spanner ring comes out. Second, there's an allen-heax setscrew at the bottom of the switch plunger. I forget the size but if you have a selection of SAE wrenches you'll find out what fits. Back that off three or four turns. The swtich should then pull out towards the head. You'll also need to push the switch button in so it won't hang up on the hole.