Pepper Spray Diodes revisited

[das234]

Sorry about that. I was looking at the etch mask side and comparing the pinout.

That's ok.  I sure do appreciate your time to help me (although I'm not sure that transistor is too happy right now.)

[Bret608]

Hey, that's cool that you have that Russian PNP handy! Let us know how it sounds and if that helps at all. Also, if your PN3565 is fried, you could try another NPN silicon as a stopgap measure. As long as the hfe is under 500 or so, it should be good enough to just make sure things are working and in the ballpark. I think JakeFuzz used a BC109 in his. More saturated and compressed, but he ended up liking it from what I remember.

[das234]

To my ear, the Russian transistor was an improvement but still not what I'm after.
How would I know if Q2 is fried?

[midwayfair]

How would I know if Q2 is fried?

Chances are you wouldn't get any sound at all.

There's another problem: Modern 3565s are higher gain than the old button ones.

Have you had a chance to take voltages yet? It's becoming increasingly hard to help troubleshoot this without them.

[das234]

Ok.  I measured some voltages this morning. 

In voltage measures 9.00v
Ground measures 0.00v
As you look at the top picture, Q1 measures: 0v at 12:00 (E?), 1.68v at 3:00 (B?), and 1.83v at 6:00 (C?)
Again, as you look at the picture, Q2 measures left to right: 3.65v, 1.33v, 1.84v
When I first probe the center and right pins on Q2, the values are essentially reversed (1.8 at the center and 1.3 at the right) but then they change and eventually settle on the numbers listed above.

These were taken with the GT309 socketed as Q1

Does that shed any light on it?

[Bret608]

Hey, I'm having issues with a "stock" specs version I just built up. I just posted my voltages too. Compared to yours, my Q2 looks similar, but my Q1 is quite different. I hope someone will be able to take a gander at these for us!

[das234]

Agreed.  I'm in over my head on this one.  It works but just doesn't sound right and I don't have a bin of spare transistors to plug in and try out.  Let me know if you learn anything. 

[Bret608]

I will indeed! Best of luck. This is the weirdest debug I've ever done. I may try flipping Q1 and see if that stops the oscillation and lets some signal through. I realize now from looking at your picture that our Q1 voltages are really similar--I was thinking about it backward!