04-05-2019, 10:29 PM
I purchased this at the radio meet two weeks ago...inheriting someone else's headache! 
But the Ingraham cabinet alone is worth that I paid for it, so I don't feel too bad.
Anyhow here's what I have. The set was recapped by the previous owner. Grid cap wires were replaced, light sockets rebuilt. In other words, he spent some time on this.
It was missing a speaker, which I had so after hooking that up and bringing the set up on the variac, I was encouraged to see no current draw and all tubes lighting. But there clearly was a problem with the volume control, it was uncontrollable. So I replaced that with a new 2 meg control and at least the volume (and audio output section) is working. But I get no reception whatsoever on any band.
Here's the Nostalgia Air schematic. Wish I could just post the actual schematic page but not sure how to post a PDF file direct.
http://www.nostalgiaair.org/pagesbymodel...017186.pdf
Going grid cap to grid cap I can inject a signal and get a loud buzz controllable by the volume control (ie, buzz gets louder as volume is increased) on the grid caps of both 6K7's, the 6L7 and the 6B6. Voltages all run 40 to 60 volts high, except for the plate of the 6J5 which is almost 3 times what it should be (it measures 288 and should be 110). Here's the breakdown:
The values in red ink are what I measure, to the left in black ink is what they should measure.
So I'm hoping someone with a keen eye (paging Dr. Terry) can give it a look and see what could be causing that voltage spike on the plate of the 6J5. Ohm-ing out the coils is next on the check list but there must be something else causing the high voltage.
But the Ingraham cabinet alone is worth that I paid for it, so I don't feel too bad.Anyhow here's what I have. The set was recapped by the previous owner. Grid cap wires were replaced, light sockets rebuilt. In other words, he spent some time on this.
It was missing a speaker, which I had so after hooking that up and bringing the set up on the variac, I was encouraged to see no current draw and all tubes lighting. But there clearly was a problem with the volume control, it was uncontrollable. So I replaced that with a new 2 meg control and at least the volume (and audio output section) is working. But I get no reception whatsoever on any band.
Here's the Nostalgia Air schematic. Wish I could just post the actual schematic page but not sure how to post a PDF file direct.
http://www.nostalgiaair.org/pagesbymodel...017186.pdf
Going grid cap to grid cap I can inject a signal and get a loud buzz controllable by the volume control (ie, buzz gets louder as volume is increased) on the grid caps of both 6K7's, the 6L7 and the 6B6. Voltages all run 40 to 60 volts high, except for the plate of the 6J5 which is almost 3 times what it should be (it measures 288 and should be 110). Here's the breakdown:
The values in red ink are what I measure, to the left in black ink is what they should measure.
So I'm hoping someone with a keen eye (paging Dr. Terry) can give it a look and see what could be causing that voltage spike on the plate of the 6J5. Ohm-ing out the coils is next on the check list but there must be something else causing the high voltage.
Greg V.
West Bend, WI
Member WARCI.org
