09-14-2014, 02:32 PM
OK, I finally got my tubes yesterday. I had done a dim bulb test over the last couple of days, with no tubes, and then with the rectifier tube only. All of that went well, so last night I installed the tubes and powered it up...
Nothing.
I poked around for a half hour or so. B+ seemed fine. Got noise/hum if I touched the 2nd detector grid, but nothing but silence on all three bands.
Then I realized that I didn't have the shadow meter plugged in. I retrieved it from the cabinet and plugged it in. Radio played!!!
So now I'm looking at the schematic and trying to figure out exactly what a shadow meter is. The schematic doesn't seem to be on NA or I would provide a link, but the symbol for the shadow meter doesn't really tell me anything about what it is (like a coil?).
So can anyone enlighten me on this? I've run other radios without their eye tubes installed and they worked.
Thanks,
Jon
Nothing.
I poked around for a half hour or so. B+ seemed fine. Got noise/hum if I touched the 2nd detector grid, but nothing but silence on all three bands.
Then I realized that I didn't have the shadow meter plugged in. I retrieved it from the cabinet and plugged it in. Radio played!!!
So now I'm looking at the schematic and trying to figure out exactly what a shadow meter is. The schematic doesn't seem to be on NA or I would provide a link, but the symbol for the shadow meter doesn't really tell me anything about what it is (like a coil?).
So can anyone enlighten me on this? I've run other radios without their eye tubes installed and they worked.
Thanks,
Jon
