04-24-2014, 09:54 PM
Sounds like you are making progress. I get the sense that your problem may be in the antenna transformer, so here are the notes I made when I worked through that section. The values noted are my measured values.
The antenna input into the primary is a wire coming down from above which does not have a solder tab. In my set, the 0.3 ohm section was open and I had to rewind it. I used 7 turns of magnet wire, being careful to wind in the same direction as the original. I found a very helpful post on this forum about that particular repair.
I would suggest trying to feed some audio riding on a 460 kHz carrier into each point in my diagram. Make a chart of where it works and doesn't work, and you can decide if your antenna transformer is working or not. If you use IF instead of some other RF frequency, you should be able to hear something regardless of the tuning capacitor setting. (In theory all of the 460 kHz should be rejected by the tuning circuit, but in practice some will make it through to the IF circuit and get amplified. This is why they have a wavetrap.)
It's hard to really trace much from your picture given the resolution limits. Simple things to think about would be to check your solder joints (a cold joint can be surprisingly tricky to figure out!) and making sure all connections have good mechanical support.
If you would find it helpful, shoot me an email address and I will send you a full resolution picture of my chassis before after restoration.
Keep trying. You are getting very close!
Roger
The antenna input into the primary is a wire coming down from above which does not have a solder tab. In my set, the 0.3 ohm section was open and I had to rewind it. I used 7 turns of magnet wire, being careful to wind in the same direction as the original. I found a very helpful post on this forum about that particular repair.
I would suggest trying to feed some audio riding on a 460 kHz carrier into each point in my diagram. Make a chart of where it works and doesn't work, and you can decide if your antenna transformer is working or not. If you use IF instead of some other RF frequency, you should be able to hear something regardless of the tuning capacitor setting. (In theory all of the 460 kHz should be rejected by the tuning circuit, but in practice some will make it through to the IF circuit and get amplified. This is why they have a wavetrap.)
It's hard to really trace much from your picture given the resolution limits. Simple things to think about would be to check your solder joints (a cold joint can be surprisingly tricky to figure out!) and making sure all connections have good mechanical support.
If you would find it helpful, shoot me an email address and I will send you a full resolution picture of my chassis before after restoration.
Keep trying. You are getting very close!
Roger
