A friend of mine picked this up for me at an estate sale last week here in Calgary. I have not had much time to look into it yet but I was wondering if anyone has any ideas which model it may be or if you think someone just used the 3 tube version box for a prototype 4 tube version etc…I will try to get it working of course…the inside is quite clean and fairly well constructed. The parts all seem to be in good shape. I will trace out the wiring in the next few weeks. This version uses four of the 230 type tubes.