11-08-2016, 09:23 AM
Well, progress was made, last night. The radio has been working since the reinstalling of the sub chassis, but the audio, while strong, was distorted somewhat. I have been going thru the chassis checking tube voltages and found the voltages of the 1st audio was WAY OFF. The plate voltage was only 26 volts, should be around 90, as I recall. With the tube pulled, I was getting around 220 volts on the plate pins, so it had to be somewhere in the voltage supply to the plate or grid circuit. Everything checked out in the plate supply. The grid circuit, with no voltages listed, was a little more difficult. I lifted the grid lead and the plate voltage came up a little. Tracing the grid voltage back to it's source revealed a misswire. It was grounded! Put back in it's proper point brought the 1st audio plate back up where it should be, and the distortion went away! I just figured that I had miss wired the connection when restuffing the Bakelite block to which it was connected, but I was not guilty in this case. After taking a look at the under chassis photos that I took, before starting this project, revealed that the lead was miss connected when I started! Either from a previous repairman or from the factory, who knows? From the photo, it looked as if it had been unmolested.
Anyway, it is playing beautifully now. Now on to cleaning up and installing the tuning dial before starting on alignment. The magnetic tuning appears to be working, somewhat, on strong signals, anyway. I don't know what to expect. Having never seen this feature before. All you have to do is come close, and it brings the station in, but usually needs a little fine tuning. Maybe after alignment it will be a little better? As said, I don't know how well this worked from new.
Anyway, it is playing beautifully now. Now on to cleaning up and installing the tuning dial before starting on alignment. The magnetic tuning appears to be working, somewhat, on strong signals, anyway. I don't know what to expect. Having never seen this feature before. All you have to do is come close, and it brings the station in, but usually needs a little fine tuning. Maybe after alignment it will be a little better? As said, I don't know how well this worked from new.
Chris H
N9WHH