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Guitar Pedal Help Answered

Hello there,

I am currently fixing a VOX Wah Wah pedal. The bypass works - the wah wah effect does not.

How exactly does one check to see if each individual component is working?
Is it by using a multimeter? How exactly can I do that? (I've put in a 9v battery and tried seeing if there was voltage around the circuit, but I think I am doing it wrong.)

Can anyone give me some tips? 

Here is a picture.



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7 years ago

You've got a fairly new Vox/Thomas/Dunlop circuit wah pedal (all basically the same circuit, only small variations). Luckily, there's lots of documentation online.

-- Look for loose wires.

-- Make sure the pedal is getting juice. Check the battery itself, battery connector, etc.

-- Check the jacks. most newer pedals have a power adapter input--that's a shorting jack which removes the battery from the circuit when external power is plugged in. Sometimes the jack can fail, and the battery connection is always open.

Check the input jack--that's also a shorting jack. It also cuts all power when nothing is plugged in (designed to save battery power, it's essentially the "ON" switch). But those can fail, too, or just get dirty.

-- wiggle that edge connector in case it's not making contact.  Trace the incoming DC to that point, and test with your meter.

Nice set of schematics for wah pedals here. DIY stompboxes has a general debugging page also. If the simple stuff fails, you'll have to take transistor voltages, etc. and delve deeper into the circuit board itself...