[EdHolland]

I think the problem is traced - to noise on the AC line. It sounded so local, that it seemed certain it was generated within the set. The thing is so sensitive, that any interference is hard to hear on another radio, but I have convinced myself this is actually the case. Coincidence of "pops" with flickering of the neon in my power strip was eventually demonstrated using another receiver - with and without the Zenith plugged in and running. A good thing too, as I was runnning out of ideas excepting possible heater to cathode shorts in one of the valves.

Last thing today was breaking down and replacing the wiring for the pilot lamp. This was insulated with some plastic or rubber that had become very sticky and unpleasant. Access to the connections on the chassis was difficult, as was opening the bulb-holder, but I wanted to replace the wires throughout.

I'm declaring this one done! (with some follow up pics when it is back in the cabinet.)