>From the photo, I see what looks to be a blue electrolytic capacitor at the top (photo is clipped). It's a long-shot, but that's almost 50 years old so I wonder if it dried-out. I had the same thing happen to me with a Heathkit that was 30 years old: small electrolytic cap dried-out, became a short-circuit, and blew-out the fuse (actually, it was a resistor that was put there to behave as a fuse).
If you have a scope, look for AC voltages across an electrolytic; that's usually a clue the cap is defective because it's unable to do any filtering. After that, look for burn-spots or corroded traces (I didn't see any on the photos). Wiggling potentiometers [I saw at least 1 in the photo] might be worth trying, but that is risky because you dont know what they do and you will probably affect the calibration. Over time, I think the wiper contact can get dirty so wiggling it might help clear-away contaminants that alter the resistance to the wiper. That pot looked like a high-quality Bourns multi-trim, so you may want to leave it alone; the cheap 3/4 turn units are the ones I consider suspect. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/a45d546c-226a-4967-9b84-1e70e8057836%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.