[RodB]

Levi, the IF frequency has nothing to do with the tuning capacitor. I don't believe replacing the grommets on the tuning capacitor would change the oscillator frequency to the point of non operation. The oscillator frequency is mixed with the radio station frequency to produce the IF frequency. Then that signal is passed through the IF stage. So, the IF stage is still tuned to the IF frequency regardless of the tuning capacitor. When the tuning capacitor is removed then reinstalled there may be a slight change in oscillator frequency which would result in a respective shift in the position of the station on the dial. If you're not receiving any signals at all, I would suspect the oscillator is not running at all. BTW, try 355 kHz on your signal generator with the power turned up. If you get a tone then it points to an oscillator problem.

[captainclock1988]

could a bad oscillator tube cause the problems I'm having? I'm asking because I know the original Rectifier tube (an 80)  was shorted so it wasn't allowing the radio to power up at all, so I wonder if the oscillator tube is bad as well? I hadn't had a chance to test every single tube inside the radio yet.

[462ron]

Levi, when I suggested temporarily tacking a small cap on your tuning capacitor to lower the frequency to 177.5KC, I was referring to the tuning capacitor in your signal generator, not the one in your radio. Since you stated your generator doesn’t go below 300KC, doing as I suggested might get you where you need to be. Sorry I wasn’t more clear on my previous post!

Ron

[RodB]

If, after replacing the 80 tube, the B+ voltages are good. Then you can move on to troubleshoot the receiver. Maybe check the audio section first, inject a signal at the ungrounded end of the volume control.

[captainclock1988]

Well I think I figured out what the problem is, it was a bad 58 Tube in the front-end section (the 1st Detector tube), and I figured out that it was one of the 58 tubes that was bad (and specifically the 1st Detector tube) because when I put my hand over the grid cap of the 1st Detector tube the radio came in loud and clear but as soon as I removed my hand the radio went silent. So now I need to locate a NOS 58 Tube for the radio and I think that should get it going again.

[captainclock1988]

OK, well a little update on this radio, I was able to locate some replacement tubes for this radio and I popped them into the radio and its still acting much the same as it did before, Its pulling in stations but I have to have the volume turned clear up to even hear anything, and I'm starting to think I might have a bad antenna coil because no matter what I hook up to the antenna lead on this radio nothing seems to affect the radio's reception, the radio will pick up signals from my signal generator by hooking the signal generator through the grid cap of the 1st Detector Tube but going through the antenna lead doesn't seem to do anything. I had to do a partial replacement of the Antenna wire lead because the original wire lead for the antenna was broken through the insulation and had some wire exposed right around where the antenna wire exited the chassis. Also would an out of alignment IF cause the radio to not pick up much in the way of stations and cause the stations that do come in to hardly be audible? I'm asking because even though the IF alignment capacitor covers on the chassis were still intact and appear to of not been fiddled with in the past doesn't preclude the idea that someone didn't mess with them in the past but probably put the covers back on the IF Alignment capacitor holes so that the radio would be complete.

[captainclock1988]

Well it turns out in the past I did have a signal generator that was capable of going down to 177.5 KC but unfortunately I made the mistake of trading it with a friend of mine at a local computer store in town for a Hewlett-Packard HP8640B Signal Generator from 1972 that I didn't realize wasn't capable of going down below 455 KC without some serious modifications that are a little over my paygrade to do, and the signal generator I had that was capable of going down to 177.5 was a Heathkit Model SG-8 Signal Generator that had a range of 160 KC to 220 MC and I had already made the modifications on it so that it could use BNC connectors rather than the old Switchcraft style Microphone connectors that came with it originally, unfortunately the computer shop that the guy I traded my old Heathkit Signal Generator to is in the middle of moving to a new location and they have no phone number to get a hold of them at currently so I'm kind of stuck right now on this radio because as I stated in my previous post, I think the IF Alignment is way off on this radio and needs a realignment and unfortunately the only signal generator I have right now that has a physical tuning capacitor in it that I could do the "tack a capacitor across the tuning capacitor" modification to is a unit that has the old style Switchcraft style Microphone jacks on it and I don't have the proper RCA to BNC adaptor jack to make it so I can hook it up to my frequency counter I have (I used to but it somehow got lost when I was moving from my old apartment to my new house.) There are a ton of Heathkit Signal Generators for sale on ePay but the cheapest one on there is $50+$20 for shipping, and its being sold as a "Parts Only" unit.

[captainclock1988]

How Common is it for the Antenna Coil or Oscillator Coil on these Radios to fail? I'm asking because when I inject a signal from my signal generator into my radio at the point of the grid cap of the 58 tube for the 1st Detector Stage of the radio, I get full blast Audio from my signal Generator but if I inject a signal from my Signal Generator at the Antenna Lead-in Wire for the radio, I get nothing but a very faint audio signal even with the volume turned up full blast on the radio and the signal generator outputting full blast. 

I would like to get this radio going but if its got a bad antenna coil then I may not be able to save this radio.

What's weird is that other than a lot of dirt buildup on the top of the chassis from sitting in someone's basement over the years or something, the chassis on this radio has absolutely no rust or other corrosion on it to speak of, and the chassis underneath was just as clean, so I'm really kind of stumped as to why this radio would be acting up like it is, because it seems like it should of been a simple replace the original capacitors and go kind of situation with this radio but so far that hasn't been the case.

[David]

Part of the fun of working on old radios. No body in 1930-1939 would think that a radio would be working 50+ years later. One thing that was done was to mix a little sulfur in the wax when making coils.

[MrFixr55]

Ohm the coil. If the primary is out, it could be that it took a lightning hit. You might be able to replace the antenna coil with a loop antenna from an AA5. You stated that touching the grid cap of the first detector gives you a good signal. What happens if you touch the grid cap of the RF Amp tube? If no signal and the tube is good, the primary of the interconnect transformer between the RF and 1st detector could be bad, likely an open primary.