heli: 55UKW (55 UKW); Admiral

Last week I was asked to go to look at a radio that needs repair. The radio is Heli Admiral UKW 55. It is huge and heavy console with a phonograph. It looks very much like the "Plauen 56 UKW" that is listed in radiomuseum but doesn't have the reel-to-reel player. The radio was bought in 1955 according to the owner.

I downloaded a schematic for an Admiral 8/11 from radiomuseum because that was the only Admiral schematic that was available. Does anyone know if the UKW 55 uses the 8/11 chassis? It looked very much the same than in the 56 UKW.

The problem is that the audio is weak. The volume control has to be in the full position and radio station selectivity is not good. I measured the voltages at the filter capacitors and they were 287 and 227 volts after the radio had been on for a while. Do these voltages look correct? I don't know what they are supposed to be because the schematic doesn't say it. The radio also hums slightly. The radio has never been serviced before. The only thing that I can think of that is wrong are the paper capacitors. My plan is to remove the chassis and take it to home and change all of  the paper capacitors. I will also change the electrolytic filter caps. It is not practical to remove the power supply section and other components so I'll need to test the radio where it is. I do realize that the problem may also be a weak tube or tubes but I think that the paper capacitors need changing anyway.

If you can give me any advice and tips of how to repair this radio I'd be very grateful.

Regards. Timo Haveri.

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Moi Timo! Jos sinulla on mahdollisuus saada kuvia tästä 55UKW-radiosta, laita ne tähän malli-lokeroon. Hyvä kuva helpottaa suuresti infojen etsintää. Translated: If you have possibilities to get pictures of this 55UKW set, please put them to this model, this because it helps where to find informations of the item. terveisin regards Lars-G PS. täytyyhän tässä vähän suomeakin joskus käyttää...ja kiitos lampuista.!

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Hi Lars-G. I'm going to take some pictures so that I'll be able to put everything back together. I'll upload the pictures here, although it seems that this model page is about a tablemodel version so it may be necessary to create a new model page about the console version (?). I have some other pictures and new models to upload here but I never seem to find the time to do it.

I would welcome some more information about this radio...

Timo

PS. Hyvä että lamput tuli perille.

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Hi Timo,

I have restored  last summer one Plauen (mit Admiral 8/11) . All "paper condenser" were in good condition and no need to replace.  Of course it depends how your Admiral 55 has been stored and used but this was my experience.

Data in the the Radio Katalog Band II by Ernst Erb indicates that both Admiral -modes, you are referring, are equipped with 14 tubes even the tube line up description is different.

By looking at the diagram you did download, it can be seen that model 8/11 has separate FM and AM sections from the antenna till low frequency input. Audio output stage has two tubes (EL84) arranged so that one tube is for low frequency and another for mid and higher frequency audios. If the Admiral 55UKW has same structure we can assume that excluding some minor possible differences, it is quite possible that both models are close enough to be "same"

Reagards

Ake

PS. Minulla on koneistokuvia Helistä ja Radiot 3/2007 lehdessä on siitä pieni tarina.

Åke

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Hi Åke. Thanks for the reply. I went earlier today and took the chassis out of the cabinet. I didn't take the power supply components with me so the testing has to be done where the radio is. A bit complicated perhaps. The radio has been stored in a dry and warm place all its life and the components look very good. The tubes are the same than in the 8/11 schematic. One paper capacitor looks like that the innards have come out from one end but it could have looked like that originally. My plan was to replace the out of tolerance resistors and all of the paper capacitors but perhaps I'll need to finally build that Isotest megger and test them. Although the owners don't mind if I "ruin the originality" with all new caps. The problem with this at the moment is that I don't have much test equipment so playing it safe would seem the best solution. The problem could be as simple as a bad tube. I could "test" the EL84 tubes and a couple of others in a known working radio but the others won't be that simple to test without a proper tester. I won't rush into anything before I know more, though. This is not a very urgent project.

Timo

PS. Luin sen kirjoittamasi artikkelin ja siinä olleen kuvan perusteella koneistot ovat aivan samat. Kuvat olisivat kyllä tervetulleita.

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