On a similar note, I started poking at the Mighty Motorola 6X12U six tube AM table radio this evening and was struck by the duality of the good / bad concept when it comes to electronic apparatus. How so? This particular radio is old enough to have waxed paper tubular condensers which are in fact parts from Hell and should be replaced on sight, yet Fabulous 50's enough to employ an early example of a ceramic circuit module.
Remember those? Rectangular dipped ceramic jobbie with something like eight wires protruding from one end. Inside (in this case) is a network of resistors and condensers used to couple a 12AV6 detector / 1st audio tube to the 35C5 audio output. Instead of repeatedly building the same circuit from discrete parts on every chassis, Rosin Core Roberta could solder in one module and be done with it. From what I can tell the time saving wasn't extreme as assemblers tend to get pretty quick when doing the same operation hundreds of times a day, but from a parts count / assembly line efficiency standpoint the module probably made sense.
So what's the duality thing?
The module is a good idea for new construction, but what if one part goes bad inside the dipped coating? Can't exactly get a set of probes in there and the chance of scoring an exact replacement today is very close to zero, so the module is probably a bad idea from a repair standpoint. However... The schizmatic does tell me exactly what's inside the module and how it's wired so I can build a duplicate if needed.
I plan to shotgun the chassis and will replace the module. Not as a modular part, but with traditional point to point wiring in keeping with the vintage.
BTW: Whoever soldered this one back in 1950 was either in a hurry or had no appreciation of Feng Shui under a radio chassis. Overall I'd rate it as sloppy since the filament lines aren't dressed away from the signal paths and some of the soldering is blob-tastic. But... At 62 years old it still plays despite resistors that have no tolerance band and Satan's waxed paper condensers.
Worth a second thought....................