grundig: Faulty Germanium transistor on City-Boy

ID: 404903
? grundig: Faulty Germanium transistor on City-Boy 
26.Sep.16 07:33
45

Ganesh Ramanathan (CH)
Count of Thanks: 5

My City-Boy had constant hissing sound which was traced to a faulty TF65 (AC125) transistor on the amplifier section. I temporarily replaced it with a bulky TF78 and it seems ok, but are there any online shops selling old transistors? I would be glad to know your ideas and suggestions. Thank you very much! 

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 2
Germanium Transistors 
26.Sep.16 18:38
45 from 1955

Michael Watterson (IRL)
Editor
Articles: 1033
Count of Thanks: 3

Many Eastern European sellers on eBay have both domestic and military "NOS" Germanium transistors of Russain or USSR origin. Just select parts with suitable voltage, power and frequency rating for the application, rather than equvalent or better spec.

I've used a 60MHz part to replace the usually faulty AF117. Audio parts other than higher power audio (such as AD161 AD162) are easier to replace than RF parts.

Western European parts are also available, but can be extremely expensive. AC125 should be no problem. Parts like AF117 are usually better replaced with AF127 etc due to tin whiskers inside the can. Littlediode is I think one western source specialising in obsolete parts. They sell on their own site and ebay.

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 3
grundig: Faulty Germanium transistor on City-Boy 
25.Nov.16 22:59
379 from 1955

Andrew Wylie (GB)
Articles: 6
Count of Thanks: 3
Andrew Wylie

TF65 are for sale on eBay quite cheaply.

Andrew

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 4
grundig: Faulty Germanium transistor on City-Boy 
25.Nov.16 23:29
383 from 1955

Rudolf Drabek (A)
Articles: 272
Count of Thanks: 4
Rudolf Drabek

Pls send email with address. I can send you two pieces. If you have a SI pnp transistor you can adapt R55 to  e.g.18k for equal emitter current of the LF-driver stage.

Rudi

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