[Reece]

The way you can think of a light dimmer is that it cuts up juice into longer or shorter pieces with blank spaces in between, longer pieces for brighter light, etc. The result is OK for an incandescant bulb but would be a buzzy mess for electronic work, and there's the power handling problem.

If you look around you could find a variac at a flea market. I got a good one in a metal case with pilot light, switch, and voltmeter for five bucks.

Your best bet until then would be the dim bulb tester. It protects as well as cuts voltage (bright light tells you to shut it down, now!) Some have used a three-way bulb, like 30/70/100 with three-way socket, of course. In that case you need to mark the switch so you know which position you're in. A bit more elegant would be made up of three or so sockets and switches with maybe 50, 75, and 100 watt bulbs; larger for larger TV's. You don't really use a variac much, usually just on first startup, so a simple one socket deal and a handful of bulbs (just change 'em to go up in voltage) is really sufficient.

Edit: I just looked at that auction you mention: that would be great. Mount in a metal box, switch, pilot light, receptacle, fuse, nice little project. Go for it!