http://www.antiqueradioschematics.or...tics-sears.htm
For seven bucks they apparently will send you a diagram. The model was made in 1946 it seems. That would, to me at least, imply tubes like 1N5, 1H5, 1S5 and so on. If the filaments are wired in series, add all the voltages to get the A voltage at 50 mA drain. The B voltage is probably either 67.5 or 90 Volts; judge by the ratings on the electrolytic capacitors.