Radio Road

I agree (FWIW), plus, I'll share my secret vintage tuner repair trick :)

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This Post Has Been Edited by the Author

In Reply to: RE: hmm, did I bite off more than I can chew for this tuner? posted by fredtr on June 26, 2023 at 05:29:41

If one has a vacuum tube tuner that "works" in an electrical sense, but not in a "radio" sense (i.e., lights up, tubes heat, power supply supplies - without getting hot(!) - audio output puts out) -- in that the radio does not receive any signal, try removing each tube (one at a time!), cleaning the pins (Q tip and DeOxit, if you like, or just a paper towel), then reseat each tube.
I've "repaired" a number of silent FM tuners just so.
RF and IF circuits are rather precisely tuned and, over decades, can go out of whack* for remarkably subtle reasons. Or at least that's my assessment. ;)
Try it! Just be careful as there are delicate things -- especially (!) 40-plus year old PC boards of at-best moderate quality to start with.
I'd "worry" more about the HV power supply more than anything else, FWIW. I'd also think about replacing capacitors in the signal path (particularly the one or two on the output side), but I'd stay the heck away from doing much of anything in the "radio" side of the circuit (including the IF stages). That said, the Dynaco tuners are meant to be straightforward to align, so they should be a bit more robust than a (nominally) better tuner to amateur troubleshooting.
PS Do be extremely careful cleaning -- especially around that "air variable capacitor" which is the user's primary lifeline, so to speak, to tuning a radio station. Don't spray stuff around it, don't bend the fins, etc.
Apologies to the OP if this is all old hat! :)

all the best,
mrh

Edits: 06/26/23

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