Crybaby stopped working....

[killerkev]

The wah pedal worked and then it didn't.  The whole story is below along with voltages etc.

1.   Dunlop GCB-95 Crybaby
2.   http://www.freeinfosociety.com/electronics/schemview.php?id=351
3.   Part Substitutions: Your standard changes that are well known.
          a.   A 100K trimpot replacing the 33K currently set at 100K.
          b.   Trimpot replacing the 1.5K currently set at 2K.
          c.   Trimpot replacing the 470 ohm resistor off of the Q1 emitter.
          d.   Q1 & Q2 transistors were replaced with work alike BC109
          e.   The buffer section was removed and true bypass was installed.

I had modified thee wah pedal and it has basically sat unused.  I shipped it to my friend in another state. I did play through the pedal for about 10 minutes before I shipped it out that evening.  It worked just fine, a nice sounding wah pedal.

When he received it, he said it didn't work. He said he only used a few different batteries to power it and not an adapter. When I got it back it exhibited the following:
1.   Passes sound both when engaged and not.
2.   No wah sound only a distorted sound with some volume change when rocking the pedal back and forth.  I changed out the 4.7uf  capacitor since I had read that can cause the pedal to behave like a volume pedal but nothing changed.
3.   I touched up all solder joints thinking something got knocked loose during transit but no change.
4.   Tried an audio probe but couldn't make anything out.

I measured the voltages at each component and wrote it in red in the picture. I hope some one can offer some help!

[R.G.]

Reported voltages look reasonable; nothing obviously open or shorted.

I'd guess that there's an issue with one of the three trimpots or a short in the inductor to start with.

Temporarily replace the trimpots with fixed resistors, then sub in a known-good inductor.

[MikeH]

A bad inductor will make a wah kind-of behave like a volume pedal.  The winds inside are very delicate, so it could be a broken connection in your inductor.

[petemoore]

  The inductor coil [intact] should have a small resistance to it, whether it's big enough for 'the meter to read [?

[killerkev]

Thanks I will take a look at the suggested components and cross my fingers......

[killerkev]

Well I found the problem. It wasn't any of the components but a solder joint that wasn't touching a trace  . But as mentioned before, the inducter does have a small resistance around 20 - 50 ohms. One more question since I've seen different schematics...when changing the value of the 0.01 uf capacitor, should it be 0.22 or 0.022uf.  I've seen both listed and it seems that moving from a 0.01 to a 0.22uf seems pretty drastic. Did some people miss typing in a zero?