Problem with DIY Clyde Mccoy wah

[I-Wi]

Hello everyone,
It's my first post on DIYstompboxes. I'm 20 from Belgium and have made a couple a pedals (not top quality build but working   ) but today
I need your help !
I build a Clyde Mccoy Clone based on this PCB and layout :



It doesn't work. When I crank my amp up I have a little sound but no wah.
Before I swap for this PCB, I made a homemade pcb based on the layout on Fuzz Central, it was untidy but did work. I switched back to the orginial V847A circuit and this one did not work ! So I bought a Mccoy PCB on Ebay, soldered every components and here what I have :
(Don't pay attention to the bad solder, it's the third time I resolder everything)












Up left, DPDT Switch :
On-off for buffer

Up left middle :
On off On resistor for sweep resistor selection

Down left :
100k variable resistor for volume (replace the 68k resistor)

Up right pot :
Not used

Down right pot :
Middle pot

DC Jack :
Ground / Red wire from battery snap / 9V for Buffer and PCB

Input jack :
T : input to 3PDT
R : Black wire from battery snap
S : Ground

OUtput jack :
T : Output from 3PDT
S : Ground

Pot :
1 : Star Ground
2 : From PCB
3 : From PCB + Output

Do you think a broken 3PDT, DPDT or the ICAR pot could do this ?

Thanks for your help !
Have a nice day !

[I-Wi]

I double check everything and nothing seems wrong... I'll try swapping the switches, maybe one is broken ...

[joegagan]

you have added many things to the basic wah, the error could be many places.
try replacing some of the added controls with fixed resistors of the proper value from the original schematic. do this one control at a time. this might tell you something.
read the debug pages here, follow the steps. use an audio probe to see where the signal is getting lost.

[I-Wi]

Thanks for the reply.

But as you can see it's only variable resistors instead of fixed resistors, so normally it shouldn't be a problem. I'll try soldering the input and output directly to the jacks to see if the PCB is a problem

[I-Wi]

I've removed every pots, swap the inductor for the stock L1A Vox, wired input and output to jacks and powered it with a battery instead of the DC jack. Still nothing ! I'm going mad !
Only two of the 4 inductor legs are soldered (the right ones !), the right values for the right component...
Do you think it can be the pot ?? It's not the original one.

[joegagan]

i understand, the added pots should not be a problem but every single added connection adds more possibilities for something to be miswired or mis-connected.

i seriously doubt that the pot change is a problem.

go back the troubleshooting guides and follow the steps.

[I-Wi]

Because of the poor PCB design, I found a mistake. I had to swap collector and base legs on Q1. Now done, it's still not working...
The battery I use reads 8.39V

Q2 (next to the 9V input)
C : 8.29V (before I swap the C and B on Q1) after : 7,61V
B : 0.49 (before) 4.77 after
E : 0.01 (but my multimeter when touching nothing shows 0.01)

Q1 :
C : 7.67
B : 0.02
E : 0.01

Can't really say what's right or wrong based on those numbers because I'm not a pro. Maybe you can

[I-Wi]

I made an audio probe.
Do I use it right ?
I clip the ground lead to the chassis and checked every solder. Each time, I touch a solder the "ground noise" stops.
My audio probe is the one from BYOC.

Edit :
I strum the strings on my guitar, and I noticed, the signal stop on the second end of the 68k input resistor
Second Edit :
I check with the audio probe before the 68k input resistor, I can hear the guitar, after, I can't. I checked on the solder and on the leg, no signal. But the multimeter reads 71k when I'm testing it... How come ??

[I-Wi]

My problem changed !
I put a 470ohm instead of the 100k that goes to ground ! That's why it wasn't working. Now I reassembled everything and I have sound but it's kind a weak wah (not volume) it does wah wah but it barely change compared to the bypass sound. On the heel down I have just a little sound and it distorts a lot !!
I first though it may be the input cap that wasn't 10nf but it's the same as the Q cap, so 10nf...
This wah is making me crazy !