Cry Baby wah pedal - volume drop randomly

[FarleyUK]

Hi all,

First time poster and newb, so be gentle

I've modified my GCB-96 Cry Baby with the following changes:

- Removed buffer and converted to true bypass
- Replaced the 33K resistor in parallel with the inductor with a 68K
- Replaced the 390 ohm resistor at the emitter of Q1 with 270 ohm resistor
- Replaced the 1K5 resistor between the base of Q1 and the inductor with 2K2 resistor.
- Replaced the 68K series input resistor with 47K

When I tested it, it was all working, but I have since discovered that there is a random volume drop, and it sometimes cuts out completely (even when not engaged). Seems to be that stomping on it can make it happen more often than not. Before I did the mods, the wah was a bit temperamental, thinking about it.... would sometimes cut out.

Here's a pic:



I also accidentally burnt and lifted a part of the track on the rear of the PCB, but bridged the gap by using a wire and soldering the contacts directly.

In work at the moment so unable to provide voltages etc., but will see what I can do when I get home.... but does anyone have any idea what the issue could potentially be?

[GibsonGM]

Welcome, Farley!   

Sounds like a loose connection/cold solder joint.   Symptoms like that suggest a mechanical issue, something that can be moved, as when you stomp.    Something could be shorting to ground between PCB and case, if it totally cuts out...

You gotta get in there, with a pencil eraser and the thing on, and push some stuff to see where it's "sensitive", then revisit your connections.  Did you change the pot at the time you did the mods?  I wonder if it's wearing out?  So work the treadle a bunch, too, see what changes.

This probably isn't a big thing, you just have to find it   Don't break the PCB when pushing on it, ha ha....

[FarleyUK]

Welcome, Farley!   

Sounds like a loose connection/cold solder joint.   Symptoms like that suggest a mechanical issue, something that can be moved, as when you stomp.    Something could be shorting to ground between PCB and case, if it totally cuts out...

You gotta get in there, with a pencil eraser and the thing on, and push some stuff to see where it's "sensitive", then revisit your connections.  Did you change the pot at the time you did the mods?  I wonder if it's wearing out?  So work the treadle a bunch, too, see what changes.

This probably isn't a big thing, you just have to find it   Don't break the PCB when pushing on it, ha ha....

Cheers - will have a poke around in there tonight... if you don't hear from me, something went terribly wrong

[duck_arse]

Welcome, Farley!   

Sounds like a loose connection/cold solder joint.   Symptoms like that suggest a mechanical issue, something that can be moved, as when you stomp.    Something could be shorting to ground between PCB and case, if it totally cuts out...

You gotta get in there, with a pencil eraser and the thing on, and push some stuff to see where it's "sensitive", then revisit your connections.  Did you change the pot at the time you did the mods?  I wonder if it's wearing out?  So work the treadle a bunch, too, see what changes.

This probably isn't a big thing, you just have to find it   Don't break the PCB when pushing on it, ha ha....

Cheers - will have a poke around in there tonight... if you don't hear from me, something went terribly wrong

"page not found" when I went to look at your pic. something went terribly wrong there. also, welcome.

[FarleyUK]

Welcome, Farley!   

Sounds like a loose connection/cold solder joint.   Symptoms like that suggest a mechanical issue, something that can be moved, as when you stomp.    Something could be shorting to ground between PCB and case, if it totally cuts out...

You gotta get in there, with a pencil eraser and the thing on, and push some stuff to see where it's "sensitive", then revisit your connections.  Did you change the pot at the time you did the mods?  I wonder if it's wearing out?  So work the treadle a bunch, too, see what changes.

This probably isn't a big thing, you just have to find it   Don't break the PCB when pushing on it, ha ha....

Cheers - will have a poke around in there tonight... if you don't hear from me, something went terribly wrong

"page not found" when I went to look at your pic. something went terribly wrong there. also, welcome.

Weird - it should be embedded... looks OK on my screen. Try here though: https://carousel.dropbox.com/photos/cc/XoVXtbsO9gVHJI7

[FarleyUK]

OK... this is very odd.....

Just took the back off the pedal, and connected it as the sole pedal in the chain to the amp. No FX loop or anything else. Different cables as well.

....and it seems fine. I've also used a one spot instead of a daisy chain from the Pedal Power 2 Plus I normally use... tried the PP2+ and it was OK as well... very odd!

Just got a 3pDT switch arrive so I'll be adding an LED and re-soldering a few bits - watch this space...