[Arran]

That's a good question Murf, I'm not familiar with the Silvertone sets as I just don't run into that many of them here, but the 1939-42 Philco sets are notorious for having failed output transformers, at least the push pull, chassis mounted ones, in their AC sets. In fact if you read the testimonials under that transformer you got one of them is from someone who needed a replacement for the one in his Philco 40-150? In any event it doesn't matter, the 40-180, 150, 195, 41-280, ad infinitim all have the same general layout, though the better ones actually have a phase inverter tube rather then the screen grid inversion setup. In my personal experience I have found maybe three output transformer failures overall in all of the stuff I have worked on, one was a Rogers (basically the same as a U.S built G.G Majestic), the second was a in an early 40s Canadian Westinghouse set, and possibly one on a Philco H series speaker but I haven't confirmed it yet.
   Just out of curiosity, with regard to these Silvertones with suspect failed output transformer primaries, are they Stewart Warner built, Colonial Radio built, or were they built by someone else? I'm just curious if there is a pattern here like there in with the Philcos I mentioned, maybe whoever made them bought them from the same supplier as Philco? It's funny that you are headed to Arizona, if you were headed to the Tempe area you could have probably saved yourself on having them shipped, maybe you still could on the ones for the other Silvertones?
Regards
Arran