1953 sylvania 172k CRT and Chassis

[Biscuithead]

Originally Posted by wa2ise

That's the power transformer, and the tubes on top are rectifiers. The high voltage secondary is centertapped, and that wire comes out on the other side of the transformer. The winding that drives the tube filaments is likely centertapped, and that wire also comes out on the other side (this wire is the B+, which feeds into filter caps). From the grounded centertap, the current goes thru about 300V of windings, then one or both tubes, and then another 2.5V of filament winding, to reach the centertap wire that becomes the B+ source.

The reason for parking rectifier tubes atop the transformer was that TV sets had lots of vertical headroom inside their cabinets, but were crowded horizontally. So save some horizontal chassis real-estate and put those tubes atop the transformer. Also being atop the transformer puts these tubes, which get very hot, up in the air and away from other parts on the chassis.

Transformer manufacturers made these transformer/rectifier tube units as one of the items in their catalogs, and TV makers saw them as a single module for their assembly line workers to install, instead of two (transformer, tube sockets) and less wiring to do.

Very cool... If no one wants this chassis, I might have to pull out that thing and get it glowing, just for glowing's sake...