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looking for help finding Audio transistors

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I am working on fixing an old bullhorn and I'm not sure what is wrong with the unit, so I am going to replace all the Capacitors and transistors in the unit.
but I am having a hard time finding the proper transistors.
here is what is printed on the transistors.
-9012 5d g e c b
-c945 q14xc

I am looking to get an exact replacement but I am not too familiar with what is interchangeable.

I would appreciate any help.




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The C945 will be a 2SC945, a readily available audio transistor.


The other two could be 2SC1702 and 2SC9012; both types exist, but I cannot say for definite.

The 2SC1702 is an NPN type rated 0.8A, 50V, 0.625W
The 2SC9012 is PNP, 500mA, 40V, 0.625W

I'd consider something like a ZTX651 as a replacement for the 1702 and a ZTX751 to replace the 9012.
There are many other possibilities, but those are available and better specs than the originals which do not seem to be available now.
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Nigel Goodwin

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Blindly replacing components isn't a good way to try and repair something, and you're as likely to cause as problems as you might cure.

You need to fault find, and see what's wrong - first job is to locate a circuit for it, or draw it out is one isn't available (as seems likely) - there isn't a lot in a bull horn, so it should be easy enough to draw out.


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[email protected] junctions rarely "wear out". It does happen when a junction goes open....ive seen it here a few times with 1N400 series diodes in the Frame Stage of CRT. But its rare. Junctions normally fail completely...so...just changing transistors etc will not solve your problem...unless you find a leaky or shorted transitor/diode junction. Other that nope.
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