Cry Baby Wah 95-910511

[misterc57]

Hi Folks.  Trying to get info on an old Cry Baby 95-910511 I want to bring back to life. 

I have two problems with this WAH; 

1. the pot sounds horrible from wear
2. when you switch the WAH off, there is no output

I read through another thread on here for this Thomas Organ WAH, all references are indicating a 100K pot.  The pot I pulled out is a 500K (AB 93869B A-500K-OHM TYPE J).  I am confused on what to use for a replacement pot (value and type).

If the recommendation is to use a 100K, there is a lot to choose from.  Looking for recommendations.

Also would like to figure out why there is no output with the switch off.  Right now I have the old pot out of the unit but could clip it back in for testing  The inside looks all original as far as wiring and switch.  I can add a photo tonight.

Thank you.

[pompeiisneaks]

I would replace the pot like for like, that 100k may be for different circuits.  The problem may be in finding one with the right specs.  Most I've seen available are 100k, but it's up to you.  You could put in the new one and see if it works fine.  As for the output part, I'd look at one of two things.  A. the switch itself is bad or needs cleaning B. the wire going from that side of the output has come loose or has a break in it somewhere.

~Phil

[sluckey]

I still have that same crybaby that I bought new in '72. The pot in that crybaby should be 100K. There are several different pots available. I suggest getting one with a fully sealed metal back on the pot instead of a rubber dust seal.

The switch issue is either a bad switch or a bad wire from the input jack to the switch.

[misterc57]

Was the original pot linear or audio taper?  Will check switch and wiring tonight.  Thank you.

[pompeiisneaks]

You can generally tell pretty quickly which.  Linear is pretty close to linear and changing it should move pretty consistently if you connect it to a DMM.  Audio is log tapered so depending on which side it's on you should either see really rapid resistance change and then really slow, or really slow for most of the travel and then really rapid near the end.

Say for a 1M it would be 10 ohm, 20 ohm half way is 1k ohm, 3/4 is 5k and then 4/5 is like 700k or something crazy like that (Not sure of hte exact values just hinting that you'll see a sudden shift)

~Phil

[misterc57]

Still no output with switch off.  I checked every wire going from switch to jacks to pot to board and all have continuity.  The switch has 3 lugs, the two side by side connect and disconnect when switching. 

What should the signal path be with the switch off?

I have attached some pics in chance someone sees something that I do not.

Thank you. 

[sluckey]

Don't get much simpler...

[misterc57]

Turned out that the switch was wired wrong, now I have both bypass and fx working.  Time to order a pot. 

Thank you to all!

[misterc57]

My new pot is installed. I am disappointed because the new pot sounds very scratchy.  I used an inexpensive pot (around $10), it is not sealed.   It has good reviews and this is the first time I have ever worked on a wah pedal. 

Just moving the pedal up/down without playing produces an undesired scratchy sound.  Could there be other issues aside from the pot or is this all about the pot?

Thank you.

[pompeiisneaks]

Sounds to me like DC is getting to the pot, you may have a capacitor leaking.

~Phil

[misterc57]

What is the approach on these old pedals and caps?  Does it make sense to look for leaks one by one or just replace all the caps?

Thank you

[pompeiisneaks]

That's a debate for the ages.  Some go on about replacing caps is a way to ruin an antique.  On the other hand, it doesn't cost much to replace them all, but that, I leave up to you.  You can try swapping them out and if each doesn't resolve it, restore the original so it's closest to 'stock'.  You can also look at what caps are the decoupling caps and/or are in line with the pot to test those and limit the shotgun approach too.

~Phil

[pompeiisneaks]

Looking at sluckey's schematic, either of those 0.022uF ones around the pot may be the culprits.

~Phil

[sluckey]

You can check for dc voltage on the pot by engaging the wah switch and connect a dc volt meter across the output jack terminals. If you have dcv then replace both of the .22µF caps that connect to the pot.

However, the pot could still be the problem. Since you used a cheap unsealed pot you can spray some electro cleaner inside the pot. Does that help? If so, consider getting a good quality sealed pot.

It can be a challenge to set the pot to give a good range of tone and a good foot action. You have to loosen the mounting nut and slightly rotate the pot body, then tighten the nut and try it out. I spent several hours getting mine to operate like it did when new.

[misterc57]

Will have a look tonight.  One of my problems is I do not know what this should have sounded like originally, came to me not working right. 

Are those .22 and .01 caps non polarized, looks that way in the schematic but in some pics I see a red line across one side of each cap.

I did try spraying the pot, did not make a difference.

Thanks for all the great advice, will update with results soon.

ps.  I assume I should see no DC at all on the output (even a small amount)?

[pompeiisneaks]

Exactly, none, the coupling capacitors job is to block DC from that side and only allow the ac signal from the guitar through.

~Phil

[misterc57]

Reading 4.5 VDC on the output jack.

[misterc57]

Thank you to all for pointing me in the right direction.  One of the .22 caps was shorted.  Replaced it and and all is working well.

MC

[pompeiisneaks]

Great to hear! :)

~Phil

[Jbassfunk775]

Don't get much simpler...

Perhaps you wouldn’t mind taking a look at my thread from this evening; “old Vox/Thomas Organ Crybaby Help”?? You’re the closest thing to an expert on the subject I’ve come across!