Boost not working on Krankosaurus

[shinychrome0]

I'm trying to troubleshoot a Krankosaurus for a friend of mine.  He got it off of someone else he knew who was the original builder.  Its got a few issues that have been there since he got it. The most troubling is that the boost circuit does not function correctly. If the boost volume is set all the way up, i can hear a tiny amount of signal coming through with the boost engaged. 

I have already double checked every component on the board, and everything seems to be built exactly to the schematic.

Also, the volume knob is extremely sensitive.  It basically goes from 0 to 9 by just barely turning it up.

[stecykmi]

the easier/best way to debug the boost is with an audio probe (or oscilloscope). just trace the signal path until it's lost, and that will greatly narrow down what could be wrong with it. search around on the forum, i think instructions for building your own probe where posted. it sounds like it might be a bad transistor though...

as for the volume problem, it might have the wrong taper on the pot.

[dwstanford]

Yeah, I would try swapping out the transistor for the boost section first (Q4 on the layout).  If it's socketed.  It should be.  That may fix the problem right there.  I posted a guts shot of my krankasauras build on the build report if you want to take a look at it.  I've tested it against a box of rock and it sounds virtually identical.  Check the orientation of your boost transistor and the value and taper on the volume pot to make sure it matches the recommended value (distortion vol. 100kB, boost vol. 5kC).  If those are correct, start checking and double checking your components.  If you plan to do much pedal building, you should definitely build an audio probe. This boost circuit is very small so with a probe, you could track down the problem easily.

DS

[shinychrome0]

So it turns out the boost issue was just a broken wire from the switch.  So the boost works great now.  I had to give the pedal back to the guy so he could use it for a show but he'll get it back to me in a few days.  I already checked and the right pots are used.