Vox Wah help

[hobojoe]

Hey everyone, I just bought a broken Vox Wah v847 re-issue in hopes of repairing it.  I looked over the board and noticed one of the caps was busted so I replaced that cap and the wah worked perfectly.  A couple hours later I go to play it again and it is still making its wah but the sound is a little scratchy,  so I inspect the board and nothing really jumps out at me and I plug it back in.  Now it does not wah at all when I move the pedal it seems to change the volume but it does not wah anymore.  Anyone have any idea what this could be? I was thinking it could be the inductor because I dont know much about wah pedals and thats the only thing I have never used before on a board.

Any help is appreciated

[LoudGreg]

"Lifting the earth connection of the 4.7µF capacitor will cancel the wah effect and leave you with a volume pedal."


From this site :   http://homepage.ntlworld.com/s.castledine/greenfuz/wah.html

Should be easy to fix.

As far as the scratchyness, you might want to change the pot. 

[jonathan perez]

that could also be a bad electro.

and believe it or not, a dead battery.

i got a wah and it was noisy/scratchy as all hell! i was pissed!

so, thanks to this site, i used really basic elimination...

i changed the battery and there you have it, rockin clean wah. 

[enigmur]

The 4.7uf cap in the vox is a Electro cap.

Just make sure you check all cable connections and solders under the board, make sure no components can move.

The pot could also be bung, but I wouldnt think that would stop it from wahing totally

[hobojoe]

THanks for the replies, I was doing a little reading and I came to the conclusion that it was the 4.7 cap (Before the replies) So I replaced it with a new one and it is still just a volume pedal

"Lifting the earth connection of the 4.7µF capacitor will cancel the wah effect and leave you with a volume pedal."

I was wondering if you could clarify because im not really sure what this means.  Could the cap have become un-ground?

As far as the scratchiness, one of the poles on the SPDT switch wasnt soldered on and I fixed that and the scratchiness has gone

[jakenold]

Check the inductor too. That can also give that effect.

[hobojoe]

Check the inductor too. That can also give that effect.

Is there any way to test the inductor other than replacing it?

[jakenold]

Check the inductor too. That can also give that effect.

Is there any way to test the inductor other than replacing it?

One way is to use a measuring device capable of measuring inductance. But you CAN check for continuity, to see if the wire around the core is broken.

[Paul Marossy]

Are you sure that the PCB isn't shorting out on the enclosure? I have an old Vox wah that did that - no sound at all when it did that. I had to stick a piece of insulating material between the PCB and the enclosure to get it to stop doing that.

[hobojoe]

Yea its not shorting because i still get sound when i have the pedal on.

I just went ahead and ordered a new inductor from small bear, we will see if that fixes it and if not ill just go from there

[LoudGreg]

THanks for the replies, I was doing a little reading and I came to the conclusion that it was the 4.7 cap (Before the replies) So I replaced it with a new one and it is still just a volume pedal

"Lifting the earth connection of the 4.7µF capacitor will cancel the wah effect and leave you with a volume pedal."

I was wondering if you could clarify because im not really sure what this means.  Could the cap have become un-ground?

As far as the scratchiness, one of the poles on the SPDT switch wasnt soldered on and I fixed that and the scratchiness has gone

Yes, being that this cap is polarized (has a + & - side) if you remove the neg side you will have a volume pedal. I did this mod on mine with a SPST switch. Being that you have already replaced it (just make sure it's oriented correctly) I don't think this is the problem.

As far as the scratchy problem  Isn't it great when you fine & fix the problem. 

[hobojoe]

Well I replaced the inductor and everything is good good thing small bear had the inductor i needed

[Paul Marossy]

Huh, I seem to be hearing more and more stories about wah pedals with bad inductors. What's up with that?! 

[hobojoe]

Well I bought mine broken with the intention of fixing it, but that still doesn't change the fact that it was a broken inductor.....

Soooo I dunno 

But thank you for all the help everyone

[Paul Marossy]

Well, in any case - Yes, I'm glad you got it working!