In article ,
rowdy yates beanboy wrote:
TO-92 case, NPN, M logo, (Motorola?). From a Tanberg 3008-A preamp.
Any suggestions for an easy sub or a spec sheet would be appreciated.
Thank you.

Motorola does make some parts with Pro-Electron numbers, but I don't
see a BC651. I do see an MPS651 NPN, 60V, 75 MHz Ft, 2000 mA max,
min hFE of 75 with no max. The lack of a maximum Hfe spec and the
high current makes me think that's a switching transistor.

With discrete transistors, you can generally substitute with impunity
on audio circuits as long as you are replacing with a part that has
the same hFE and the same or higher maximum voltage and current ranges.

If this a stereo preamp, you are in luck because you can find the
identical transistor in the good channel, measure the voltage across
collector and emitter, and then take it out and measure the hFE with
the transistor tester function on a multimeter. This gives you enough
information to get a good match, though you will want to replace both
channels to make sure they are exactly the same.
--scott

10 to 500 which makes it look more like a switching transistor to me.


--
"C'est un Nagra. C'est suisse, et tres, tres precis."