This is just a quick go through for me. If I was serious, I'd find more. But, for starters;
- The Albany Ham Radio Association (k2ct.net) will have a flea market 'listing' on their website, and swap meets that I can't find dates for just yet. But their office is on Delaware Avenue. Ham Swap Meets are where I find lots of test equipment.
- Troy is a 15 minute drive North of Albany, and Troy also has a Ham Radio Club. They also have an online 'For Sale' page, and have swap meets.
- If ham radio swap meets aren't for you, try old TV service shops, as I've said. Without knowing the area as well as you, I go with cool names and ads that say they service TV's, VCR's(!), and radios. There's John Greco Color Service in Cohoes, PMB Electronics in Troy, Lake Electronics in Albany, Madison Radio in Albany, Electronics Specialists in Albany, and that's just a start.
There has to be a supply house in town, or people who sell parts to these TV shops. That could be (it's hard to tell from their Yellow Page ad) Wells Communications in Troy. I go in and ask if they still see any old timers buying parts, and get a name. Anywhere I go, I get names, or at least leave mine. Even leave your name at all the ham radio swap meets you check out (if you check out any). Just tell them you are playing with old tube radios (that'll get their attention), and would like some test equipment to help learn. Heck, I've walked away with tube manuals, tubes, or even parts like a loaded set of Sprague Orange Drop capacitor drawers. That was cool and weird at the same time, as there was a .02uF drawer and a .022uF drawer as an example. Apparently 'exact value' was critical to some color burst circuits. None the less, I had enough Orange Drops to redo a lot of amplifiers.
There are no 'dead ends'. If you strike out at one place, ask about any old time radio guys in town. They will have some cool test gear for tube equipment. Always remember; way back then a good tube tester was very expensive, so no one threw them out. Good luck, and do tell me what you find!