[MrFixr55]

+1 on all the comments.

Zenith advertised their chassis as hand built but the later ones had these conical metal connectors on phenolic strips mounted to the metal chassis/ these conical connectors also surrounded the tube sockets. these connectors were above the chassis and open underneath. The components were stuffed into these connectors, then the chassis likely went through a solder pool similar to the wave solder pool used on PC Boards, so slightly hand built. I went nuts trying to fix a zenith color set that "ghosted, toll I found the cold joint between one of these posts and a tab bent up from the chassis, that served as a ground. This was also a common issue on the PC Board solder points to the chassis tabs that supported them and served as chassis ground.

I Had several XL100 sets from that German store "Offen der Streit" that I fixed and gave away. (I think my youngest brother still has one). When I bought a nice RCA Demensia (never bought the companion HiFi components), they went to single PCB, likely for 3 reasons:
1. It was cheaper.
2. Yes, solid state devices were proven to be more reliable.
3. Most of all, too many intermittent connections from the plug-in boards!