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realtone-j: Transistor replacement question

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Forum » Radios and other type of sets (Physics) etc. » MODELS DISPLAYED » realtone-j: Transistor replacement question
           
Richard Varner
 
 
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21.Apr.19 23:37

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Hello,

I've been troubleshooting a Realtone TR-970 and the MW oscillator is dead.

Fortunately, I have the excellent schematic and parts list.

The oscillator transistor tests as damage -- it's a 2SA153 PNP , according to the parts list, which matches the spec printed on the transistor.

According to the Radio Museum website this is a germanium diffused high-frequency transistor.

Question: Can I replace this PNP with a silicon 2N3906 PNP transistor intended for general purpose low-power amplifying, or do I need a replacement more specifically matched?

Thanks ...

Hilmer Grunert
Hilmer Grunert
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22.Apr.19 00:28

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Hello Richard,

no, that type doesn´t work for AM-Oszillator. 2SA153 works up to 60 MHz.

Comparison types are AF124-AF125-AF126 or AF200

many greetings

Hilmer

Richard Varner
 
 
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22.Apr.19 01:55

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Many thanks! 

I now understand that an NTE 126 will also work.

 

With kind regards,

 

Richard

Richard Varner
 
 
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09.Jun.19 18:46

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Still working on the same radio.

 

I needed to replace the audio driver transistor, an NEC 2SB113 -- PNP germanium.

 

Can I replace with a general purpose silicon PNP 2N3906?

 

Thank you.

 

Richard

Günther Stabe † 19.8.20
Günther Stabe † 19.8.20
 
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09.Jun.19 20:47

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Reply  |  You aren't logged in. (Guest)   5 Hello Richard,

you may try to replace with a PNP silicon type - it might work. With a mA-meter to control the current (~ 10...20 mA) and with your ears to check the sound / distortion...
It's not easy to find a matching "old" germanium transistor for little money in the States, so try it.

Best regards,
Guenther

By the way: please scan and upload the schematic - other collectors in this world may be happy...

This article was edited 09.Jun.19 20:50 by Günther Stabe † 19.8.20 .

Richard Varner
 
 
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10.Jun.19 20:06

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Thank you.

 

I've attempted several times to upload but so far have not succeeded.

 

I will keep trying.

 

Best regards,

 

Richard

  
rmXorg