[Today’s run: rest day]
After nearly another day wasted on this old radio I finally found the problem.
As frequently happens, most of the exercise was the result of a self-inflicted problem. I replaced a capacitor because I thought it was the wrong value. It wasn’t. And when I put in the new one I accidentally touched another part and made a very small flaw on it, which turned out to be the thing that caused the hours of searching.
I finally found the problem. A small RF choke near the replaced capacitor was damaged. I had to wind a new one. (My inductance/capacitance meter comes in really handy for this!) Once I did that I was pretty much back in business.
I still have some VFO voltage regulation problems. I put in a new zener diode. We shall see if it can take the heat and dissipation. If that doesn’t hold up I can go to a three-terminal regulator or get a bigger zener.
But the thing is playing now. It still has the chirp on CW. I talked to a guy tonight in Ohio and he said the chirp was not objectionable.
I’m glad I was able to eventually find the problem. I enjoy the search. I’m not really very organized about it. This case was the usual: last thing touched turned out to be the neighborhood of what had gone wrong.