Admiral 4204 ch.B6

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Admiral 4204 ch.B6

Post by Ben Delk on Fri Jan 18, 2013 9:18 am

Anyone have an Admiral 4204 ch.B6. I have an unidentified non-electrical part.
http://tasha.eecs.umich.edu/Antiques/Radios/templ.php?pid=410&collection=Radios




Ben


Last edited by Ben Delk on Fri Jan 18, 2013 8:10 pm; edited 1 time in total (Reason for editing : add photos)
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Re: Admiral 4204 ch.B6

Post by Bill Cahill on Fri Jan 18, 2013 9:51 am

Very scarce set, and, very nice. I know alot of the beautiful wood grain is fake, but, still, a very nice radio.
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Re: Admiral 4204 ch.B6

Post by Ben Delk on Fri Jan 18, 2013 11:26 am

I recently purchased one, overall not too bad condition but the dial string and dial pointer are missing but that doesn't appear to be a huge problem. However there is a part directly behind the tuner wheel string wheel that pivots up and down that I have no idea what it is supposed to do. I thought I had the pictures of the part on my iphone but I don't so I'll need to post them later today.
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Re: Admiral 4204 ch.B6

Post by Dr. Radio on Fri Jan 18, 2013 9:10 pm

Oooh, ooh (in my best Arnold Horshack voice)...

Found a tiny schematic (IPhone makes things interesting.)

Ben,

See that little straw looking tube? There should be an iron slug in it that raises up and down as you tune. It appears your radio has a tuned RF amp stage. Most manufacturers would simply install a tuning gang with 3 sections. Not your radio! As you tune, the cam causes what should be a spring loaded lever to rise and fall which in turn raises and lowers a ferrite core rod in and out of the tube (a coil) below.

They must have been looking to use up their supply of two gang variable capacitors. Thus the Rube Goldberg device.

I'm actually surprised...Zenith patented this idea in the 1940s for there Am/Fm radios. They used a cam attached to a regular tuning gang. The tuning gang did the AM tuning and the cam raised and lowered 2 ferrite rods for FM tuning and oscillation. The spring loaded action helped keep drift down and the ferrite tuning worked well at the higher frequencies. Now just who copied who? *cough cough* patent infringement....

Do I win a prize? LOL Very Happy
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Re: Admiral 4204 ch.B6

Post by Ben Delk on Sat Jan 19, 2013 10:39 am

The winner is .....the man with the Arnold Horshack voice.
I found this little rod in the bottom of the case when I disassembled it. I had sneaking suspicion it had something to do with my unidentified part. This is one of those times when a picture would be worth a million $$ and all the parts priceless. Anyone have one of these radios of one built like it where I can get a picture?
Thanks DOC!!!!

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Re: Admiral 4204 ch.B6

Post by Ben Delk on Wed Jan 30, 2013 10:39 am

Well I managed to get the ferrite rod reconnected to the screw now I need to figure how the spring that keeps tension on this mechanism is suppose to do that. It is attached but just flops around. I finally found a spring for the dial string and got it on but need to make a dial pointer. Funny... the recap and wiring has been the easy part on this radio. Finding or making missing parts is always time consuming and a pain in ***.
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Re: Admiral 4204 ch.B6

Post by Ben Delk on Sun Feb 03, 2013 6:14 pm

Admiral 4204 ch. B6 is complete






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Re: Admiral 4204 ch.B6

Post by Guest on Sun Feb 03, 2013 7:36 pm

Great Job!

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Re: Admiral 4204 ch.B6

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