Germanium Transistors

Hello Radio Enthusiasts!

Although this forum maybe only for tube enthusiasts, I take the liberty to ask about transistors. I got in my possession a Philips 10 RB 960/33 tuner from the early sixties, it’s very good sounding apart from the left channel which is silent. This tuner is made of germanium transistors and the problem is now, where to find these transistors. I’ve some experience of silicon transistors which almost always go open when fried while the germanium ones will be shorted and thus damaging surrounding components. The transistors I’m searching for is AD149, AC125 AC132 and AF118 and I would be very grateful for any information where to find them.

Kind regards

Lars-G. Lundelin

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Just a wild suggestion!

Did you attempt applying a little heat to the problematic transistor (I don't mean too hot) and then cold?

See what happens.

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AC125 is available from:
http://www.dil.nl/UK/home.asp
There are several AD149s on offer on ebay right now and one French seller is offering some AC132s


Peter

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A very peculiar fault with the AF11x family of transistors is the growth of "whiskers" inside the can, which short out elements of the transistor. Sometimes a temporary "fix" is to unsolder the shield lead. It seems odd but this often "cures" the problem.

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Hi Lars!

Ask germanium transistors from Partco Oy,Helsinki.

same for Finnish: Kysäise niitä tranisitoreja Partco Oy:stä,Teuvo Pakkalantie ,Haagassa.
Ainakin heidän luettelon mukaan löytyy osa noista,ja vastaavat niile jotka on jo loppuneet varastoista.

terv,Jukka

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Hi Omer!

Interesting, haven't tried that yet but I'll give it a chance.
Thank you for the advice.

Lars-G. Lundelin

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Hello Peter!

Thank you very much for the information and it seems that I even could find them in my own country but this URL will be added to my bookmarks. Thank You.

Lars-G. Lundelin

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Hi Mike!

Thanks a lot for the advice. Once I read somwhere that Ge-transistors were much more unreliable than tubes. I'm starting to believe it now.

Lars-G.

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Hi Jukka!

Thank you for the information. It's good to know that these components still can be found here in Finland.
Suurkiitokset neuvosta tulen ottamaan yhteyttä sinnepäin. Tässä koneessa ovat elkotkin aika lailla rasittuneen näköisiä.

terveisin

Lars-G.

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Link to Partco :  www.partco.fi 

Ohessa linkki Partcon sivulle,sieltä löytyy heidän komponenttiluettelonsa PDF:nä, +päivitykset
jos on tullut muutoksia.

Se mitä sieltä ei löydy,sitä ei tarvitse .. ;)

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Hello,

I recently obtained some Germanium Transistors from E-Bay, you can get most things although you may have to wait a long while. A bit like how long would it take, for a group of monkeys, to write the complete works of Shakespeare? I then did some searching and European members may be interested in the following url for Dial Electronics.

http://www.dialelec.com

They stock, or source, semiconductors of all kinds, including some hfe graded germaniums !!! Prices looked reasonable, I'll certainly use them in the future !

By the way I recently joined, in the past I trained at the BBC and at college, worked for Marconi Instruments and did customer service engineering at Datron/Wavetek. It always amazed me in the last job how much old test equipment was in use, but not quite as much as when I'd repaired some of it !!! There really is no end to human ingenuity, at least I hope not.

I mentioned this site to my brother, he's a Radio-Ham and puts together the magazine of the RSGB. Personally, I think this site is brilliant !

Michael

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As Mike Izyckz said, it is usually the AF11x series of germanium transistors which seem to cause most problems. There is no point in replacing these with old stock AF11x transistors as these will almost certainly also cause problems in the future, even if they have tested ok now. I have found that the silicon transistor type BF450 can be used as a substitute for most of the AF11x series without requiring any other circuit changes. They can be obtained very cheaply from most suppliers.

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I have some unused AF118s available.
In case of interest, you may e-mail me directly.

Best regards,

Gidi Verheijen

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Hi!
Very interesting indeed. I must say that I had a thought about this when servicing my radio but then a got spare Ge-transistors from a member and it's now working fine but next time going to try a silicon substitute.
Thanks a lot for the information.

Lars-G. Lundelin

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