Help finding sub for Transistor

[toddbailey]

anyone know how to find sub for a transistor marked

GE
1822
or

609
OGE or DGE

is this even a valid part number?
any specs? NPN or PNP etc.

fyi found in 100 watt audio amp as a driver to tip 31/32 pair

thanks

 

[keith1200rs]

GE1822 doesn't seem to be a valid transistor. Could it be a 2SK1822 - TO220 MOSFET? It doesn't sound a likely drive for a TIP31/32 though. A picture may help as it may show a logo.

Keith.

 

[toddbailey]

Did mosfet technology even exist back in the early 1970's for mainstream consumer audio equipment?

OK, here is a image of the part in question:

I removed the heat sink to see if there was any other identifying information, there wasn't any. Those are 1/2 watt resistors, btw, for size comparison.

 

[keith1200rs]

Oh, I see. Yes, that's old. I will have a look when in the next couple of days, but it does look like an old GE part. Internet information for something that old is unlikely.

Keith

 

[toddbailey]

I'm in the process of creating a schematic, not fun.

Once I have a basic flow I can have a better idea of what is going on.
In testing I see a clean sine wave going in and a clipped sinewave coming out.

I'll have to research how to determine if it's a NPN or a PNP transistor.
As I recall it has something to do with polarity at the E or C terminal.

At least on the back side of the pcb, are the letters E B and C, in most cases.
so that helps

Being an audio amp, the choice of available parts is sizable, I can scan the NTE database and probably find something.

I suspect that I just need to take a series of voltage measurements then select a part that has spec's that exceed them by 10 % or so
But I've never had any sucess in part subsitution.

To add to my pain, I haven't done analog service in over 30 years.
Other than replacing old caps, resistors and a few blown xformers with new in a old McIntosh tube amp.

 

[keith1200rs]

I wonder if it is old enough to be germanium? I will see what data books I have but I don't have much before the 1980s.

Keith

I've had a look in my old data books but cannot find anything. I had hoped an old cross reference guide may have listed it, but I couldn't find it. I also had a look in an old book of reference cicruit designs to see if it was in there, but no luck.

Keith.

 

[aslamp]

I'm also trying to find subs for these that are in a Harmony B1200 17W Bass Amp. Did you have any luck finding anything out?

Maybe the GE stands for Germanium? Weird, I know, but possible?

 

[aslamp]

I'm gonna try subbing them with some BJT's and see what happens