Colorsound Inductorless Wah Troubleshoot

[neddyboy]

I'm building a Colorsound inductorless wah into a Crybaby shell. I used Paul Marossy's 6/10/05 board design, but redrew it a bit larger as I had to hand-make the traces. I don't have a board etching setup. URL for layout: www.diyguitarist.com/PDF_Files/ColorsoundWahPCB.pdf‎

The bypass works great (!), but I get nothing when I trigger the wah. Zip.

Photos of the boards:
http://s825.photobucket.com/user/jonathanisneddy/media/colorsound-inductorless-top.jpg.html?sort=3&o=1
http://s825.photobucket.com/user/jonathanisneddy/media/colorsound-inductorless-bottom.jpg.html?sort=3&o=0

No two schematics are the same for this thing it seems. Marossy's calls for a 470 ohm resistor just before the jumper to the sweep pot, but several others call for 330k. I've tried both. I started with a 2N5088 replacement from NTE, but it got lost during troubleshooting so I put in a 2N3904. Several sites suggest it as a viable substitute. The only other substitute is a 5.6M resistor instead of the 5.7M.

I've rechecked all the values, the connections, tested the battery, etc.

[R.G.]

http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

[neddyboy]

I'm going to assume that your brief message was intended as a reminder to include voltages.

Battery unclipped: 9.08v
Red lead to board: 9.08v
Black lead to ground: 0v

Q1 voltages
C: 0v
B: .57v
E: 8.59v

[R.G.]

I'm going to assume that your brief message was intended as a reminder to include voltages.

Yes, at least that.

Ideally, you'd tell us which of the schematics and parts values you actually used. I'll guess at the values on the project file you listed.

Q1 voltages
C: 0v
B: .57v
E: 8.59v

The collector is supposed to be pulled up to +9V, and the emitter tied to ground. Is the device reversed in the board or the labels reversed on the voltage list?

[neddyboy]

Ah, I see. I used all correct values except for the ones stated. 5.6M ohms instead of 5.7M, plus the transistor substitution.

Q1 was reversed. The graphic on the parts layout I'm following had the flat side of the transistor facing left and I put it in that way without thinking. I must have checked it a dozen times and missed it a dozen times. Thank you!

[R.G.]

You're welcome!  Glad I could  help.

That's one of the virtues of the (laborious, PITA) procedure of measuring all the voltages of the active devices. It forces you to look at things another way, and flushes out things you can't see because you've looked too many times. I say "you" in that because I actually developed that approach to make ME look at things a fresh way. I get too-close-to-it blindness really, really easily.