Grumpy Caputchin no sound

[mviggen]

Hi. I made a grumpy capuchin or bad monkey. I get sound when bypassed and the led lights up when stomped, but then I don’t get sound. I am suspecting there migtt he be something wrong with the mmbfj201. Anyone know what resistance or other things I can measure on it while it is on the board? I know I can put more solder on the switch, but I don’t think that is the problem so far since I get bypassed sound and led light when engaged (although no sound).

Grumpy

[mviggen]

The instructions say q2 should be switched, and so it is… readings on ic’s:
ic1: 7.8, 7.5, 1.2, 0, 8.4, 7.8, 7.8, 1.5
Ic2: 4.2, 4.2, 4.1, 0, 8.4, 7.8, 7.7, 7.6

[FiveseveN]

1. Schematic
2. Op amp biasing is no good but I don't think you got the pin order right so it's harder to tell what's going on. Pins on an IC are counted counter-clockwise:

[mviggen]

Yes you are right… I counted from top to bottom on both sides so 1-4 was right but then the next 5-8 was inverse

[FiveseveN]

OK so
1. Schematic pretty please? How else are we supposed to know what things like "Q2" are supposed to be doing?
2. Did you check the biasing?

[mviggen]

https://pcbguitarmania.com/wp-content/u ... Docs-1.pdf

The building docs including schematics

[mviggen]

Since this time I discovered that there were parts of the pcb that was supposed to have connection that does not. So I figured I will try to build this thing on vero instead

[jimilee]

Since this time I discovered that there were parts of the pcb that was supposed to have connection that does not. So I figured I will try to build this thing on vero instead

Sounds about right.

[Lani]

Do these people even test the PCBs they sell? Which connections are you referring to?

[jimilee]

Do these people even test the PCBs they sell? Which connections are you referring to?

I doubt it, this seems to be a common issue.