According to [M Caldeira], the Blaupunkt Sultan 24300 was one of the last tube radios made in the 1960s. He’s got one but it needed some tender loving care, and you can see how he approaches a restoration like this in the video below.
The radio was actually in better shape physically than most of the old radios we see. It wasn’t perfect, but it looked good on the outside. Electrically, though, it did need some work, and the dial had problems, too. The first obstacle was identifying exactly the model of the radio since there were a number of Sultan radios produced.
Armed with the correct model number, he could find the service documentation. The radio apparently was made for the international market because the service information was in both English and German. It also had a transformer you could configure for different line voltages.
The insides didn’t look too bad, either, although the old printed circuit board was brittle. This video is just part 1 of the troubleshooting and we hope to see some more video soon. But it was great to see inside what looked like a premium tube radio from the 1960s and we can’t wait to hear it working again.
Can’t ressist must watch the video because of the cat in the background. Thank god it’s only 48 seconds. :-D
I have a Blaupunkt Granada, also from the 1960s. Just like the Sultan, my Granada has a selectable line voltage. Also just like the Sultan, my Granada has a setting for 155VAC.
Does anyone know what country might have used 155VAC? I have not been able to find anything that mentions that particular voltage.
Specifications of the Sultan:
https://www.radiomuseum.org/r/blaupunkt_sultan_24300.html
Specifications of the Granada:
https://www.radiomuseum.org/r/blaupunkt_granada_20300.html
My blog posts on the Granada:
https://josepheoff.github.io/posts/1blaupunkt20300-toc
150..160 V was used with early small private hydro plants that were not connected to a grid, often located in the alpine regions and serving just one valley or an industrial outfit. A 150V setting can be found on most tube radios made in or for southern DE, AT and IT.
Please forgive my ignorance, I’m American. What places are southern DE, AT and IT?
Germany, Austria & Italy at a guess.
DE = Deutschland = Germany
AT = Österreich = Austria
IT = Italy
Do you have a link to something describing these old systems and their power distribution? I haven’t been able to locate anything useful.
Auch wenn es in Deutsch ist – ich kann Deutsch und Englisch lesen.
You could reduce 240V to 155V with voltage divider made from 1k and 1.8k resistors.
Sure, if you don’t care how much energy you waste heating your resistors (and recalculate to account for the load resistance you haven’t accounted for)…
There’s a reason why the radio has a multi-tapped transformer.
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Sure, if you don’t care how much energy you waste heating your resistors.
Or you could just use a multi-tapped transformer like the one in the radio…
There’s no need to reduce the voltage from 240V to 155V. The Blaupunkt radios have an input power selector that lets you switch the radio to operate properly from 240V.
I just wondered where on Earth 155 VAC was used for consumer connections.
One of the first Hackaday videos I’ve gotten my wife interested in … because of the cat! 🤣
So, will it play Dire Straits?
There’s a lot of stuff on archive.org, but you won’t find much about local power distribution for small plants in the early 1900s. Those were often shops with water-powered line shafts that were modernized with electric gear and the installations were customized to fit the needs and the budget. There were also no standards for line voltage, the only guideline was that a carbon arc needs 50…60V, so for lighting purposes an integer multiple of that was chosen.
Maybe this book provides some insight: Handbuch der Elektrotechnik, 7. Band, Elektrische Centralen
https://archive.org/details/handbuchderelek00jentgoog
That was supposed to be a reply to Joseph Eoff (October 9, 2023 at 2:38 am).
Thank you for the link. I’ll see what that book has to say about local generator voltages.