06-23-2019, 02:31 PM
Ed
No, the radio does not make the noise with the 27 removed.
Now we might be getting somewhere. I switched 27 tubes around and on the 4th one, it kept putt-putting but it began to receive the local Spanish station which broadcasts at 990 kc. Only it is receiving it at 1350 on the dial - with the tube shield off. As soon as I start to put the tube shield back in place, before it even touches the chassis, reception disappears.
Just for fun, I twisted the high frequency oscillator trimmer around a bit, with the tube shield off - and the frequency did not change.
Obviously there is an issue in the oscillator circuit.
I had not rewound the oscillator coil (or the antenna coil, or the RF coil) because it tested good. Perhaps I should pull it, remove the winding that typically goes bad, bake it, rewind it, and try again. I think I will also replace mica cap (9), 410 pF, because heating it up on both sides to remove/replace wires may have damaged it. That has happened to me before.
No, the radio does not make the noise with the 27 removed.
Now we might be getting somewhere. I switched 27 tubes around and on the 4th one, it kept putt-putting but it began to receive the local Spanish station which broadcasts at 990 kc. Only it is receiving it at 1350 on the dial - with the tube shield off. As soon as I start to put the tube shield back in place, before it even touches the chassis, reception disappears.
Just for fun, I twisted the high frequency oscillator trimmer around a bit, with the tube shield off - and the frequency did not change.
Obviously there is an issue in the oscillator circuit.
I had not rewound the oscillator coil (or the antenna coil, or the RF coil) because it tested good. Perhaps I should pull it, remove the winding that typically goes bad, bake it, rewind it, and try again. I think I will also replace mica cap (9), 410 pF, because heating it up on both sides to remove/replace wires may have damaged it. That has happened to me before.
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Ron Ramirez
Ferdinand IN
