That darn Hallicrafters S-40A has been a real bear to work on. Everytime I think I have it fixed something else goes wrong.
This week has been NO exception. Now when I turn it on, I get a loud crackling across the speaker, even with the "Sensitivity" AND the Volume control turned fully clockwise. It is very loud also. I did find that by pulling tubes out one at a time through the different sections of the radio, that when I pulled the noise limiter/BFO tube (6H6/ V7) that the noise stopped.
Another odd thing is that the V7 tube has pin's 1 & 8 soldered together, and 250Vdc coming from the 6SK7 tube. Pin #1 on the 6H6 tube just happens to go to the metal case of the 6H6 tube. Found that out while pulling it out and getting a light shock. What a fun radio.
Ok, so pull the tube out for now, since I use it mainly for shortwave listening during the day when I am working in my shop/shack/office. Don't need CW/SSB anyway. I have a feeling that the voltage to the 6H6 tube is also the cause of my crackling when it is first turned on. Going to dig into it again tonite and see what happens... If I dont survive then I will be giving the radio away....