Thanks for that guidance. I took the PLL board out and removed it from the can so I could examine the foil side. I checked every square inch of that board with my focusing loupe (...I do large format photography, too...) and a flashlight and I could find no weak or cold solder joints.
Not on the PLL board but on the main board, there is a lot of that glue that is blobbed onto the base of some of the components that has turned brown. Should I chip away at it with a small jewelers screwdriver? Or is there something that I can use on a Q-tip that would dissolve it?
I'm wondering if the PLL might be OK, but there may be some signal from the PLL that is being shunted to ground because of that glue?
If I am not successful finding the problem, do you still repair these radios? To be honest, I no longer have any test equipment other than my VOM... so I'm not sure how much diagnosis I can do other than look for shorted or open components and check for voltage at specific points. I just boxed up my TS-850SAT to send out for repair (similar symptoms, actually...) and thought I would get the 10M HTX-100 going while the 850 is away... LOL All that's left is to try my homebrew 20M QRP rig.
Thanks, again for your guidance. And I have really enjoyed watching your videos. I wish YouTube had been a thing back when I was active the last time.
Wes, WB2SVF