Pepperspray 2018 *** SOLVED ***

[mattc]

I built the giveaway pepper spray board to original specs, but I'm getting no output.

Voltages:

In: 9.14v

2n404a
C: 18.8mv
B: 44.2mv
E: 0v

2n3965
C: 9v
E: Starts at 8.5v and then drops
B: 0v

I did a signal trace of what I think is the audio path and I get signal all the way to pin 2 of the Balance pot.   

Any ideas?

[jimilee]

Are the pots soldered to the board, If so, you need to add a lot more solder?

[mattc]

I just added more solder, and then did a continuity test between the pcb and the lugs on the pots, they're all good... still no sound

[matmosphere]

Check to orientation of the 3965. Those are tricky to install correctly. If you have a tester that shows the pins it is really helpful in identifying the pins.

[madbean]

Something is definitely amiss at Q2, which is why Q1 also has incorrect voltages. Not sure what, though. You seem to have the correct resistors. If you've looked at the build pic it will show where the flat side of Q2 (that's the emitter) is oriented. Maybe make sure your tantalum caps are also correctly oriented. They should have a + mark on each of them.

Since they are socketed, try taking out both transistors, then measure the voltage on both sides of R3 and see what you get.

[mattc]

Check to orientation of the 3965. Those are tricky to install correctly. If you have a tester that shows the pins it is really helpful in identifying the pins.

Good Call!  I put it on the DCA and realized that I hadn't oriented it correctly.   It's working now.    When I was troubleshooting, I tested it to see if it was working, but didn't write down what each leg was.   

Thanks everyone for the help.