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PostPosted: Wed Nov 30, 2016 1:56 am 
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Location: Victoria, BC
My wah pedal intermittently turns off when using it. I still get a sound but no wah. I've had this problem for quite some time. I recently replaced the entire PCB because it was broken, due to so many modifications. The pedal uses a momentary switch. I checked the switch but the same problem still persists. Sometimes it seems that, if I smack the pedal, it starts working again. I checked the DC power adaptor to see if that's the problem and it doesn't appear to be. I checked the switch to make sure that it's working and it appears to be fine. I don't know where to begin in terms of diagnosing this problem. I'm starting to wonder if one of the wires might be bad and it's periodically not making a connection. By bad, I am not referring to the solder joint, but rather the wire is internally broken. I'm also wondering if it has something to do with the switch. Would a momentary switch start to break internally because all of the on/off banging against your foot that it endures.

Any help would be greatly appreciated.


Last edited by oldschooldirt on Wed Nov 30, 2016 9:40 am, edited 1 time in total.

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PostPosted: Wed Nov 30, 2016 2:04 am 
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That photo came out excessively large. I added it through an ipad, which may be the problem. I'll get a gut shot of the pedal in the AM.


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PostPosted: Wed Nov 30, 2016 9:40 am 
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Here is an inside photo of the pedal.

This is my plan. Please let me know if I'm on the right track.

Step 1: I'm going to play with the pedal until it stops working. This means that the pedal will be engaged but I won't be getting any wah sound from it, I'll just be getting a true bypass sound. When this happens, I'm gong to keep the pedal stable so that it doesn't move then I'll check all the connections in the switch to make sure that they are working. I'll use a DMM to do this. The purpose of this is to rule out the possibility that the switch is faulty or one of it's wires is internally broken.


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PostPosted: Thu Dec 01, 2016 12:57 pm 
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Ok, I did a preliminary step before testing the switch, as I didn't have enough time last night. I had to practice :roll:

I rocked the casing back and forth and activated the momentary switch repeatedly in the hopes that I would get the pedal to stop making a wah sound, which it did. I got the same sound with the pedal on or off, a true bypass tone. At that point, I placed one lead form my DMM on the pcb board's battery eyelet and the other on the corresponding dc adaptor lug. I did this for each of the dc adaptor's lug and their corresponding eyelets on the pcb. When doing so, I made sure not to touch the DMM leads off the connecting wires, as I wanted to rule out the potential of a faulty connection or a bad dc adaptor. I received continuity for all connections. Therefore, I believe it's fair to assume that there isn't a problem with the pedal getting power, nor is there a problem with the dc adaptor.

One Observation: I wiggled the white wire with the yellow heat shrink on it and the pedal came back to life. I kept wiggling it and the pedal continued to work... but for how long.

My next step is to test the switch with some jumper leads. If anyone has instructions on how to do this, posting them would be greatly appreciated. I did this test once but have since forgotten how, and have lost the instructions. I did it about a year ago.


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PostPosted: Mon Dec 05, 2016 11:21 am 
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To test the switch, connect you send wire to your return wire.

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PostPosted: Thu Dec 08, 2016 1:14 am 
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Ok,

So this is what I have tried so far:

I still don't really understand how to test the switch, despite searching around on the internet. I did try the steps in this video but it didn't seem to make sense for me. Any explicit guidance on this would be greatly appreciated :)

https://www.youtube.com/watch?v=jegykkfW2RA

I then connected a 3PDT switch to the wah pedal with alligator jumper cables. This didn't seem to make a difference at all but I don't think I was doing this right anyway. I suspect that connecting the 3DPDT switch would be useless while the momentary switch is still connected as usual.

I then connected the pcb 'in' to the pcb 'out' with an alligator jumper cables. I did this when the pedal wasn't working. By not working, I mean the momentary switch was actuated and I was getting a guitar signal but not wah sound.

I then followed the pcb 'in' wire wire back to the momentary switch, and did the same for the pcb 'out' wire. I then connected those two lugs with an alligator jumper cable when the pedal was actuated but not giving a wah sound. This made no difference.

THEN THIS HAPPENED:

I turned the pedal upside down so that it was lying guts up. That way, the momentary switch is constantly actuated. I sent signal through the pedal with my guitar and slowly moved the chassis back and forth in order to get a wah sound, which I was getting. THEN I NOTICED THIS! When I would drop the chassis down so that it landed in a toe down position (my pedal chassis is very loose), I could hear a slight pop sound and then the pedal would stop working. I would then rock the chassis back and forth for a while and no wah sound would occur. Then I would drop the chassis down again, hear the pop sound, and the wah would start working again. This went on for as long as I kept doing it.

Then, when the pedal was not working, I touched the pcb's edge, right next to the jack eyelet on the same side as the input jack. I then heard a pop and the pedal came back to life. I got the pedal to stop working again by dropping the chassis down in the toe down position again, and then was able to repeat the same process of getting it to work again by touching the pcb's edge in the exact same spot. I then got the pedal to stop working by slamming the chassis down again.

I then decided to loosen the screws which hold down the pcb. Once I did that, the pedal came back to life again. Unfortunately, this was very short lived. I put the pedal back together by screwing in the rubber feet and used it normally for a few minutes. The same thing continued, it would stop working with a hard toe down but I could get it to start working again by repeating the same motion. There was no consistency to it though. It's kind of like hitting an air conditioner with a wrench; sometimes it works on the first hit, sometimes it works on the fifth hit.

MY HYPOTHESIS: I'm wondering if, because I have so many braided wires from the 4 pots (Q, Bass, Mids, and Gain) stuffed under the pcb, the vibration of the chassis from rocking the pedal is causing a break in the circuit somewhere. I'm not even sure if this is possible.

NEXT STEP: I have no idea. I could take the pcb out and move those pot wires so that their not underneath the pcb any longer. My only hesitation to doing that is accidentally causing more damage. I'm on my second pcb with this pedal because I did so many mods in the past that I ended up damaging the first one.

Any suggestion would be greatly appreciated :)


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PostPosted: Thu Dec 08, 2016 12:40 pm 
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Sure sounds to me like a funky wire connection somewhere....

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PostPosted: Thu Dec 08, 2016 2:03 pm 
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It does doesn't it.

Because I am still getting sound when the pedal is actuated, would I be able to detect the 'funky wire connection' with an audio probe? My guess would be that the signal is still going through the board but in a rather intermittent manner, if that makes any sense at all. My limited understanding of electronics is that the signal either has continuity or it doesn't. Maybe I'm wrong on that. I guess the question for me is, "If there is a funky wire connection, wouldn't I just get a short or a signal break." The result of such would mean no signal at all when the pedal is actuated. Maybe I'm totally wrong on that.

I'm also wondering if it would be wise to actuate the pedal but in a way where it is not giving me a wah tone. Then place an alligator jumper on the 'tip' of the input jack, which is attached to one lead on my DMM. Then trace the pathway on the board with the other lead of my DMM, starting at the 'in' eyelet, to see if I don't get continuity anywhere.


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PostPosted: Thu Dec 08, 2016 2:07 pm 
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If you overheated the foot switch, it's possible it wouldn't reroute the signal, but more often than not, you just lose signal.


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PostPosted: Thu Dec 08, 2016 2:30 pm 
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oldschooldirt wrote:
Because I am still getting sound when the pedal is actuated, would I be able to detect the 'funky wire connection' with an audio probe? My guess would be that the signal is still going through the board but in a rather intermittent manner, if that makes any sense at all. My limited understanding of electronics is that the signal either has continuity or it doesn't. Maybe I'm wrong on that. I guess the question for me is, "If there is a funky wire connection, wouldn't I just get a short or a signal break." The result of such would mean no signal at all when the pedal is actuated. Maybe I'm totally wrong on that.

I'm also wondering if it would be wise to actuate the pedal but in a way where it is not giving me a wah tone. Then place an alligator jumper on the 'tip' of the input jack, which is attached to one lead on my DMM. Then trace the pathway on the board with the other lead of my DMM, starting at the 'in' eyelet, to see if I don't get continuity anywhere.

For an intermittent problem like you have described, I'd suggest that you power up the pedal (connected to your guitar and amp, of course) and then poke around the PCB and the wire connections with a non-conductive probe--a wooden chopstick is a favorite, but anything made of wood or plastic should work. You want to listen for changes in the audio output while you're probing. This is often an effective way to find that bad connection.

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PostPosted: Fri Dec 09, 2016 6:26 pm 
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So the momentary switch rides on the foot treadle, right? My money is on a damaged joint or internal fracture in one of the wires connected to the momentary switch. The movement of those wires over time (and rocking) could have broken one inside the insulation or stressed the solder joints, leading to a break that makes the wah think the switch is in bypass. Second guess is a mechanical problem with the contacts inside the switch itself.

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PostPosted: Sun Dec 11, 2016 6:50 pm 
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Just for the hell of it, use a Dremel to file down the interior painted area where the input and output jacks connect. There should be solid metal on metal contact. In the past, this has been an issue with wah pedals I have modified.

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PostPosted: Thu Dec 15, 2016 11:16 pm 
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So, I took the braided wires that connect the Q pot to the board and placed them on top of the PCP, as opposed to underneath it. This appeared to make a difference for a few minutes. Unfortunately, the same problem is persisting.

I have a feeling that it may be a broken wire between the PCB and the switch. I have half a mind to simply get rid of the momentary switch, as I will likely eventually move to a looper wehereby the wah pedal is continually on. That said, I used braided wires, as opposed to copper wires, to connect the switch. My thinking was that the braided wires are more supple and less likely to develop an internal break.

Question: I would assume that, in order to check the quality of the wires connected to the momentary switch, I should rock the pedal back-and-forth until it no longer gives a wah sound, and then check continuity between each end of each individual wire that is connected to the momentary switch. Does that seem like a reasonable plan or am I missing something?

Question two: is there a way that I can add an additional switch to the pedal without actually removing the momentary switch? I'm thinking of a simple modification so that I could bypass the momentary switch. If the pedal was then working when the momentary switch was bypassed, I would know that it was a problem with the momentary switch or the wiring connecting the momentary switch.


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PostPosted: Wed Dec 28, 2016 1:51 pm 
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Yup! It was the momentary switch. I guess with the movement the wiring eventually became internally fragmented so that it would work intermittently. I was told my lots of people, including the guy at Small Bear Electronics, that 'wires that wiggle will eventually break.' I gave it my best shot in terms of trying to 'mad scientist' my wah pedal but I have come to surrender to the traditional ways of a 3PDT switch :)


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PostPosted: Sat Dec 31, 2016 2:38 pm 
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Nope! I spoke too soon. The pedal continues to intermittently shut off. It has something to do with the range knob. When I turn the knob clockwise against itself, meaning that I'm not actually 'clicking' the switch to another range cap. Instead, I've turned it all the way clockwise (as far as it can go) and then wiggle it a bit, the pedal stops giving me any wah. I then wiggle it some more and the pedal starts working again. I think I either have a faulty range switch or there is a slight wiggle/vibration in the pedal when I'm using it that triggers a wire with an internal break, causing the wah to stop working.

I am half tempted to rip all the mods out of it and return it to its stock settings; no pots, no range switch, no buffer switch, etc...

This pedal is driving me crazy and has become my nemesis. I'm not having fun anymore :(


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PostPosted: Sun Jan 01, 2017 1:22 am 
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A New HOPE!

When I rebuilt the pcb on that wah pedal I was using a soldering iron that was pretty old. It was causing me quite a few problems; solder sticking to the iron, cold looking joints. Unbeknownst to me at the time, I was suppose to replace the tip. After the wah pedal was built, I started building an analog chorus, which didn't turn out all that well at first. The pedal gave me some tone but it was very faint. After a bit of searching on this forum, I decided to re-flow all my solder joints and the pedal sang nice and chorusie :) After taking a look at my wah pedal, I noticed a lot of bad solder joints so I re-flowed them. BINGO! The pedal seems to be working fine. In hindsight, I didn't need to rip the momentary switch out of the pedal. That said, I'm not sure if a momentary switch is really worth it anyway.

If the pedal doesn't work again, I'll post about it on this forum and then go into therapy :)


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PostPosted: Mon Jan 02, 2017 1:05 am 
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Looks like I'm in the market for a therapist.

The pedal worked for about 50 minutes and then just completely stopped working. I get a signal when it's in true bypass but nothing when it's on. I've put it away in my closet. Very frustrating :evil: Unfortunately, I just don't have the time to tweak it and try to figure it out, as I have a battle of the bands competition coming up. I know I can eventually fix it when I have the time. My suspicion is that it's a bad wire.


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PostPosted: Sat Jan 07, 2017 6:29 pm 
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A stroke of complete luck.

I pulled the pedal out of my closet just to take a quick look at the pcb section that is right below the DC adapter. I was a bit concerned that I accidentally scratched the track off the pcb because the screw from the DC adapter was rubbing up against it. When I did that, I noticed that the + wire from the DC adapter was disconnected. I soldered it back on and the pedal seems to work. :)


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