Tubes for it are still available, but 67 1/2 Volt "B" batteries haven't been made in decades. Maybe someone out there has an Al Diem MiniPak converter (model 14, 6V input 140V output). Still looking for the CG 5 channel reed receiver, I've got the Bonner servos, and escapement. I even have a Veco Smog Hog kit, Veco wheels, and Veco tank for the full effect of RC of 50 years ago.
I did see some "B" batteries at the local Batteries+Batteries store within the last year. It surprised me that they were still available. Don't remember what sizes they had in stock but whatever they were they were very expensive. Using the DC to DC convertor is a much better source of the HV for the old transmitter.
John Wis
Scottsdale, Az