Cherrybomb: No Sound When Engaged

[ddavis20341]

Hi all,

I put together a Cherrybomb build the other day with BC184s, but couldn't get any sound out of it. After triple checking everything and going through some of it with an audio probe (and then walking away and checking it again), I couldn't find anything wrong.  I thought I might have reversed the pinouts with the swapped-in BC184s, so I tried to take them out and flip them around, but in the process managed to lift a number of the pads (which hadn't happened in any other builds).

I put 2N5088s in after cleaning up the remaining pads to make sure that the pinout was correct, and did some point-to-point wiring for the legs with lifted pads. I still have no sound out of the pedal, and after checking the voltages realized that the voltages across the transistors were constant whether or not the pedal was engaged (and are pretty far off from the listed voltages).

Any advice on what to do/check going forward would be greatly appreciated. I'll post voltages and pics below.
Voltages:
Q1: C - 3.49, B - 3.49, E - 3.06
Q2: C - 2.9, B - 3.5, E - 2.8
Q3: C - 7.4, B - 2.2, E - 1.6

[jimilee]

got bypass?

[somnif]

Are you perhaps shorting to the back of the pots?

[ddavis20341]

Yep, clean signal comes through fine. And I made sure the pots were clear of the leads before testing, even with the longer wires sticking out

[ddavis20341]

Update:
Not surprisingly, the signal breaks down around Q1. It comes into the base fine, but I don't get signal on either of the outside legs (even above where they meet the pads, which I don't fully understand), and additionally there is no signal across R1 (it comes in fine on the C1 side, but on the far side where it meets the emitter of Q2 there is no signal).

[jimilee]

Replace q1 and look for shorts to ground after the base where there should be none


Sent from my iPhone using Tapatalk

[ddavis20341]

Replaced Q1 and after some more poking around with an audio probe realized there was a place where the trace was cut within the board. Wired point-to-point across there, and now it works fine! Thanks for the help, glad to finally get this build off the ground.

[jimilee]

Replaced Q1 and after some more poking around with an audio probe realized there was a place where the trace was cut within the board. Wired point-to-point across there, and now it works fine! Thanks for the help, glad to finally get this build off the ground.

Awesome, nice job!


Sent from my iPhone using Tapatalk