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Dick James
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Re: Schematic Courtesy the Museum of Broadcasting
Dick James   11/18/2013 2:37:51 PM
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I can confirm the comment about lugging batteries around; my father worked for the original Curry's store in the UK before the war, and aside from folks bringing in  batteries for recharging, he used to have to collect and deliver them on his bicycle (Old Man Curry was too cheap to have a delivery van).

Another story from that era was the gas-powered radio - I didn't believe it until I saw the repair manual - literally a gas burner heating up a bank of thermocouples! Thats what you call letting the set warm up..

grover_gren
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Rookie
Re: Old electronics
grover_gren   11/18/2013 6:42:14 AM
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@David no dis intended to anyone - it's great that folk are still getting pleasure from using kit like this (apart from seeing how well it burns ;-) )

Also the war stories from those who were there are great reading! Keep 'em coming! 

BTW age-wise I'm closer to old fart than sprung chicken :-)

Thomas88131
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Rookie
UX201A
Thomas88131   11/17/2013 3:21:16 AM
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Hi!

Nice tear down! Thanks for sharing. If you want to read more about the UX201A tube used in here, check my post on my blog about it:

http://vinylsavor.blogspot.com/2013/10/tube-of-month-ux201a.html

Some people like me still use these today

 

Best regards

 

Thomas

 

MeasurementBlues
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Blogger
Re: Old electronics
MeasurementBlues   11/15/2013 6:14:27 PM
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My father's Zenith was from 1951 or so. He had it with him on Korea during the war.



Bert22306
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CEO
Re: Old electronics
Bert22306   11/15/2013 5:59:45 PM
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Speaking of Zenith Transoceanic, my dad got one too, in 1966. Did you look at the schematic? It had a really basic AM section, which includes the SW bands of course, and it had a single IF of 455 KHz for all AM bands. Not the best way to keep intermodulation products under control.

Not only that, but in 1966, schematics were still drawn as if they were for tube circuits. So just as tubes are usually shown on top, so were the transisators of the 1966 Zenith Transoceanic.

I guess I'm saying that the Zenith Transoceanic sort of followed the same simplicity of design paradigm as this Radiola, although of course from the superhet era.

Then we got a Grundig multiband radio with dual-converion IF ...

kartys
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Rookie
DO NOT USE 3-in-1 Oil
kartys   11/15/2013 5:05:53 PM
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I have read that 3-in-1 Oil cleans so well because is highly alkaline, which will only make things worse.  Using oil for electric motor bearings (or just plain 10-weight oil) would be much better.    

Bruce Bailey
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Re: Nice Design
Bruce Bailey   11/15/2013 4:54:20 PM
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@BobsView, 11/15/2013 - "TRF  Forget about that one":

I'd say that's pretty accurate statement ...  Looking the orthogonal arrangement of the tuning coils, the designers were doing their best to reduce coupling across the stages.  I can only imagine tuning across the dial, headphones on and coming across a strong station while having the volume up to pull in a far away station.

I liked the linear arrangment of the tuning dial.  The designers went to some extra effort to design and build a nonlinear capacitor.

Bruce

Graham Bell
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Freelancer
Re: Nice Design
Graham Bell   11/15/2013 4:41:03 PM
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I found the schematic for the Radiola 16 at the Museum of Broadcasting .  Click on the thumbnail for a larger view.   Notice the the use of a grid-leak detetctor. Enjoy!



http://www.museumofbroadcasting.org/16schemLo.jpg

BobsView
User Rank
CEO
Re: Nice Design
BobsView   11/15/2013 4:07:26 PM
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TRF (Tuned Radio Frequency)  Forgot about that one.  The challenge was to provide enough gain without the whole unit going into oscillation.  Took quite a bit of engineering to make it work.

Also it was difficult to get all the stages to track over the full frequency range so gain suffered at certains parts of the dial.

Superhetrodyne solved a lot of the problems.  Once the IF strip was aligned, you never had to worry about it after that.

Thanks for reminding me about that.

 

bk11
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Manager
Re: Nice Design
bk11   11/15/2013 3:57:19 PM
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Generally one section was for the Local Oscillator, one for the Mixer and the one for the Antenna input.

Superheterodyning came along later, no local oscillator in this beast.  There are three stages of tuned RF amplification.  The ganged cap was an improvement over earlier models that required each section to be tuned seperately.  That kind of made you stick with one station, as it was slow and difficult to change stations.

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