I bought an old White's machine at a junk shop called a Coin Getter. By the looks of it, I'd guess from the 1970's or 80's or so. It's got a very small coil and the component box has one knob and a speaker.
I got it for a few bucks because it didn't work. I took it apart, checked some wiring, changed the battery and it actually works! But I can't find any info on that model, like it's age, what it sold for back in the day, etc. It appears to be very,very entry level.
Any of you guys familiar with White's ever heard of a Coin Getter? I'll include a pic of it this weekend.