06-16-2012, 02:56 PM
Ok Now the shadow meter is behind me and it was successful and I have cleaned the chassis as well as possible, I reassembled the tubes and shields and fired it up....
I had no sound at all from the speaker, The speaker is fine and when I change settings on the tone control I get a small pop. I checked the volume control, it's bad..reading 4-8 meg, should be 350k max. Replaced it, still nothing, so I checked all the voltages...all within limits. Before I stated checking voltages I had no hum either at the grid caps when I touched them.
Here is where it gets a little goofy, I flip the chassis over and touch the top of the 75 tube...it hums. I touch the top of the 6a7 I get reception...for 30 seconds then it stops, but only at the grid cap, nothing through the antenna connection and only while it is connected to the tube. If I remove it it goes silent again. Now my readings on the 6a7 are 100 VDC P-K s/b 180 and 90 VDC S-K s/b 175.
I'm leaning toward a bad solder connection, but before I go back through all the connections (there are many) any suggestions as to where I should start first? It has to be in the rf section,
Here is a link to the schematic:
http://www.nostalgiaair.org/PagesByModel...013125.pdf
Thanks for your help,
Glenn
I had no sound at all from the speaker, The speaker is fine and when I change settings on the tone control I get a small pop. I checked the volume control, it's bad..reading 4-8 meg, should be 350k max. Replaced it, still nothing, so I checked all the voltages...all within limits. Before I stated checking voltages I had no hum either at the grid caps when I touched them.
Here is where it gets a little goofy, I flip the chassis over and touch the top of the 75 tube...it hums. I touch the top of the 6a7 I get reception...for 30 seconds then it stops, but only at the grid cap, nothing through the antenna connection and only while it is connected to the tube. If I remove it it goes silent again. Now my readings on the 6a7 are 100 VDC P-K s/b 180 and 90 VDC S-K s/b 175.
I'm leaning toward a bad solder connection, but before I go back through all the connections (there are many) any suggestions as to where I should start first? It has to be in the rf section,
Here is a link to the schematic:
http://www.nostalgiaair.org/PagesByModel...013125.pdf
Thanks for your help,
Glenn
Happily back in Illinois..not.
