Snack Shack Troubleshooting

[Invertiguy]

I like to think of myself as a fairly competent pedal builder. I've got probably a couple dozen builds under my belt so far, and the vast majority of them have fired right up with no major issues, including several fairly advanced projects. This isn't to say that I've never made a mistake, but up until now it hasn't been anything more major than mixing up the occasional wires or forgetting to mount an IC in its socket. This makes my current predicament even more humbling and frustrating: I finally got around to building and boxing my Snack Shack giveaway board, one of the simplest and lowest parts count projects I've ever done, only to find that the damn thing doesn't work!

Now, I'm no stranger to doing the odd bit of troubleshooting; as I said, I have made the occasional dumb mistake before. I've been looking this thing over for awhile now, however, and I've gotta admit that it's got me stumped. The offboard wiring seems fine: I'm getting power, it passes signal in bypass, the LED lights up, and I can trace signal to the board. However, I'm not getting anything out when the effect is engaged. Using a signal generator and an oscilloscope I can trace the signal up to the input side of C1, after which it becomes significantly attenuated. Signal is present at the base and collector of Q1 and all three pins of Q2 at the same significantly attenuated amplitude, at which point it disappears. Voltages on the two transistors are as follows:
Q1E: 0.000V
Q1B: 0.627V
Q1C: 1.144V

Q2E: 1.144V
Q2C: 1.847V
Q2B: 1.144V

Personally I find it really odd that the Q2 Emitter voltage is identical to the voltage on the Q2 Base/Q1 Collector, which suggests a short somewhere. I can't see any obvious solder bridges or touching leads however, and I've cleaned the board with isopropyl alcohol to remove any excess flux in case that was an issue. I'll probably come back to this later today for a closer look with fresher eyes, but in the meantime if you have any thoughts or suggestions I'd be happy to hear them!

Here are some pictures:







And a close up of the board itself:

[mauman]

I think you nailed the solution: Q1 collector is shorted to Q2 emitter.  Those 2 points are adjacent on the PCB.   Run a hot soldering iron between them on the solder side and I bet that clears it.  I've seen similar issues with an invisible line of solder between 2 adjacent points, you'd swear there's nothing there but a hot iron clears it.