02-11-2014, 07:23 PM
The lead isn't anything that was there originally.
After I restored it and nothing came out at all, I disconnected the antenna and hooked up a scope probe to pin 2 of the 36. The oscillator was working perfectly. I reconnected the antenna and the radio played fine. Disconnected that lead, and it stopped. Instead of the probe I just have an alligator test lead now, that works the same way.
It seems to me the capacitance would be miniscule, a fraction of a picofarad. I guess that's a statement of how poor the oscillator circuit is. Anyway, I just bought three 36 tubes on ebay, I hope that will fix it.
Greg, I'm sure you've seen it a dozen times, but replace the cathode bias resistor on the 36 tube with something less. I used 6k8 ohms.
After I restored it and nothing came out at all, I disconnected the antenna and hooked up a scope probe to pin 2 of the 36. The oscillator was working perfectly. I reconnected the antenna and the radio played fine. Disconnected that lead, and it stopped. Instead of the probe I just have an alligator test lead now, that works the same way.
It seems to me the capacitance would be miniscule, a fraction of a picofarad. I guess that's a statement of how poor the oscillator circuit is. Anyway, I just bought three 36 tubes on ebay, I hope that will fix it.
Greg, I'm sure you've seen it a dozen times, but replace the cathode bias resistor on the 36 tube with something less. I used 6k8 ohms.
