The P-B roundy is probably a RCA clone. You have to look into that.
P-B squares were there own. They combined hand wiring & PCB's.
Quite well built. The only thing was the OEM CRT's were not up to snuff.
A replacement from Zenith, Sylvania or RCA gave them much more
snap. Not many P-B in the NE. Most I saw were 18, 19" sets
made by GE or Panny.
From the top Zenith chassii rather boring. Just a steel chassis & tubes. The hand wiring is all underneath.
Motorola roundys, 23 & 25" tube jobs the same.
As far as no dealers go that would be rare. Every medium szed town around hear had a Zenith AND a RCA dealer. They also carried one or 2 low priced lines.
Admiral, Syl, etc so I dont think thats it.
73 Zeno
LFOD !