[Guest]

Hi I had a question on an old radio I just picked up to restore. The problem I am having is the labels are all gone and I can not get a model number. It has 4 bands, 8 tubes and I believe it may be a farm radio. The plug has what looks like a tube base connector on it and 2 additional yellow wires. The tubes line up with the 643 tube placement chart and in pencil 46 is written on the chassis. The Cabinet is the standard 643 640 style. Did these have an external power supply? I can not figure out this plug arrangement and it looks factory. When I get it cleaned up I will get pictures of the chassis up. Thanks Lochlan

[Ron Ramirez]

Hi

a 643-A is a 643 with an extra ballast tube connected in the filament circuit.

As for 643B, the B = Baby Grand (in your case, a tombstone style cabinet).

You need the schematic for the radio to figure out the various pins on the battery plug. The two extra wires are, most likely, for the "A" (filament) supply. I do not have my schematics next to me so am going from memory. YMMV.