New radios and a question

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New radios and a question

Post by willy3486 on Mon Oct 10, 2011 10:31 pm

I went to the music city vintage show and had a blast. I went thinking I wouldn't buy any and wound up buying four. I got started on one,its a Truetone. Its the big white one on the right here in this photo




To say it was a mess is a understatement. I had to clean out the mouse nest and take the tuning cap/framework out. Here is the chassis out. The speaker is totally shot. I will have to fabricate a new speaker mount.



The radio had so much rust but the good thing is that it looks like the transformers and under the radio had no rust. The volume control,the shaft to the tuning cap and the tuning cap were all rusty. I was able to spray and get the cap loose. The volume control and the shaft the cap turns with was rusted worse. As per a suggestion over at the other site I used brake fluid to loosen it. I dripped a little brake fluid on the shaft and then cleaned it with a scotch brite pad. I then dipped a little more on the shaft and heated it with a soldering gun. After a few minutes it was loose. I put brake fluid on the shaft as well and it got loose. Here it is all apart.




One issue I had I was worried about was a brass wheel that the tuning shaft would turn. The gears on the shaft would turn the gears stamped on the brass wheel. From someone turning the shaft the brass piece had the teeth warped on it. I was able to fix it by using a special pair of pliers I have. It is a flat,wide set that has on grips cut into it. They work really well to twist tabs. I used them to flatten the teeth back into shape. I then used a small screwdriver to open open up the space between two teeth. I then used the pliers to flatten it again. After this it worked perfect.

Now on to my question. I am about as rusty on tube radios as the chassis is. Here is my tuning capacitor. The tab that the wire was soldered to that goes into the circuit has broke. on each side there is a flat piece of metal that looks like the tab is made on. It is soldered to the fins on the frame. Anyway the underside of the radio is made the same way it looks like .When I take a reading on the tab and the solder it is connected. So I am wondering to fix the rusted tab could I just solder a wire to the area the solder is at next to the broken tab? The area around the broken tab is so rusty I can't get a firm reading. Anyway thanks in advance and enjoy the photos.


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Re: New radios and a question

Post by sprman on Tue Oct 11, 2011 9:48 pm

Try a clip lead 1st if it works then solder ..Easy to undo it that way befor you solder anything.Make sure everything is cleaned spotless . I use 409 mixed with ammonia to clean up very dirty stuff.Seems to work well.Sprman : )

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Re: New radios and a question

Post by willy3486 on Tue Oct 11, 2011 9:56 pm

Hey Sprman you were there as well,correct? Didn't you have a table also? I think I bought some stuff maybe from you. Was yours the one with the old atwater kent that had all the tubes gone? I always don't buy something then regret it. That would have been mine. Even though it was a mess I really like this and I am estatic with it. This is the style and type I like the best. Anyway if you out towards Smithville look me up.

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Re: New radios and a question

Post by sprman on Thu Oct 13, 2011 6:22 pm

Ihad the Collins R-388 and the Zenith T.O. 3000-1 and the small Fridge at my table along with Trains mags..Yes i was there..Sprman

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Re: New radios and a question

Post by willy3486 on Thu Oct 13, 2011 11:26 pm

I think the table I was thinking about was next to you. If I had known I would have introduces myself. I was busy looking at all the parts around the table. As far as the radio I was able to clean the tuning cap and get it to work as far as I can tell. I have been able to trace the signal all the way to the second IF transformer. The signal stops there and then I can inject a signal on the secondary of it and get it to go to the speaker.

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Re: New radios and a question

Post by willy3486 on Fri Oct 14, 2011 11:53 am

I got it!! This was a hard one to fix but its done. The big issue that was stumping me yesterday was It was acting weird. I had been able to tune a station and then trace it with a signal tracer to hear. I could also inject a 400 hz sine wave and hear it to the speaker but all of a sudden the tuning stopped. I found out that was caused by the voltage on my variable power supply down to about 40 volts. I must have bumped it.

So I traced it back to the IF transformer after that. I could get signal to it fine and on the other side I could inject a signal fine. So I figured it was the IF transformer. I was able to read a about 30 ohms on each side of it so I figured the two internal coils were good. I took it out to look at it better. I opened it up and saw that the two caps made into the ceramic top of it were corroded really bad with rust. I tried to take it apart but it was corroded to the point I didn't think cleaning would help.

I looked in my junk box that has transformers and all I found was one almost identical except it had a different coil setup. The ceramic caps were almost the same. So I got brave and took the ceramic cap off the one that was in the junkbox. I then set it up next to the one with the bad ceramic cap. I then proceded to transfer each of the 4 wires off the old if transformer to the new cap. I got the four on but one wire was heavily corroded at the solder pin and crumbled. So what I did was to take a small copper wire from a cat 5 network cable and wrap it on the post. I then carefully wrapped the corroded wire and then heated and applied solder. I then put it on again.

I then turned it on and no sound period. I injected a signal and nothing. I got to looking at the radio and one of the speakers wires had broke. I fix that and turned it on. The thing came on and I could hear the normal AM static. I tuned the tuning capacitor and was able to pick up a few stations. I then tuned up the IF transformer and found it was almost perfect in the location it was. So now all I have on this one is the putting it together and the cosmetic stuff. As far as the if transformer after the repair it tested out at around 70 ohms instead of the 30 ohms it had been. I figure the rust and corrosion on the caps had shorted it out. I was glad I hadn't forgot how to work on these things .A piece of advice though, if you are getting back into them find a easy one first. This was a pain to fix.

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Re: New radios and a question

Post by Bill Cahill on Fri Oct 14, 2011 5:03 pm

Congradulations. That's part of the problem, joy of restoration. You think you've got an easy one, but, DO YOU?
Congradulations.
Bill Cahill

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Re: New radios and a question

Post by sprman on Fri Oct 14, 2011 6:29 pm

Good job Willy, some radios can be easy to fix others can be PITA.Yes my table was next to the one with all the parts.Maybe next time in Spring we meet! Good luck getting everything cleaned and working great..Sprman : )

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Re: New radios and a question

Post by willy3486 on Fri Oct 14, 2011 11:49 pm

Thanks folks. Believe it or not I didn't run into a lot of issues with the IF cans before. I only remember one I had to repair before out of hundreds I have fixed. Yesterday I was wondering why I ever got back into these again and thought about selling them off. Then today after this one I will be glad its put together so I can start another one . u have some in mind that had a issue that might be this. I will drag them out and see.

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