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Vintage WAH repair?

Discussion in 'The Stomp Box' started by NoTeleBob, Jan 17, 2021.

  1. NoTeleBob

    NoTeleBob Tele-Meister

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    I have Cry Baby from the late 70's, circuit photo below, Model# 95-910511. Has been working fine over the decades but gets minimal use.

    I let it sit in the closet for a couple years and just pulled it out. It's throwing oscillation and massive amounts of noise when switched on. If I have it all the way back the tone is as expected (dull wah), but advancing the pedal to any forward point at all results in nasty noises. It doesn't have to be moving - just adjusting the pedal forward a smidge gets the noise.

    It's not the basic pedal wiring... the sound is fine with the wah section switched off. I unscrewed the circuit board and looked over the bottom side. There are no obvious bad or degraded solder joints (but I didn't reflow anything).

    Where should I start checking?

    [​IMG]
     
    uriah1 likes this.
  2. MojoTrwall

    MojoTrwall Tele-Holic

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    Changing pot.
     
  3. Dismalhead

    Dismalhead Poster Extraordinaire

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    I have an '80s Cry Baby. I knew it was getting noisy, but it was so gradual I didn't realize how bad it was. A couple of months ago I took the old pot out and tried to clean it with electrical cleaner, but it didn't help. Bought a new pot and it's like a brand new wah.

    Just tried to look up the pot I bought but I can't figure out where I got it. It cost about $20. Just make sure to pull your old one and match the ohms - I think they put a different pot with different ohmage in the more recent models.
     
  4. Peegoo

    Peegoo Poster Extraordinaire

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  5. Ringo

    Ringo Poster Extraordinaire

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    I have that same exact Crybaby, the original pot is still good in mine, but I did rewire it with a DPDT switch so that it is true bypass, and I have a replacement pot for down the road.
    Your wah shouldn't need a lot of TLC to get it in working condition again, as has been mentioned a new pot, I'd change the switch out too and clean / tighten the input and output jacks, and it will be ready to wah for many more years!
     
  6. Slap Axe

    Slap Axe Tele-Meister

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    I have a Crybaby that’s 20 years newer than yours, mid-90’s, that started making a lot of unwanted noise. Mainly a scratchy pot type noise so maybe a little different than what you described, but for what it’s worth, here’s what worked for me.

    I was going to just replace the pot, but tried running some contact cleaner down the shaft into the pot first. It made no difference at all, so as a last resort before buying a new pot, I drizzled some WD-40 down the shaft into the pot and it’s been flawless for about a year now. I know it’s not a conventional or recommended move to silence a pot, but...it worked.
     
  7. NoTeleBob

    NoTeleBob Tele-Meister

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    This doesn't seem to really be a dirty pot issue... it's a screaming oscillation along with lots of noise. I could see the noise coming from a bad pot but not the oscillation.

    BUT, what do I know. I'll experiment a little. If it's the pot, I should be able to simulate values with another pot wired in to test (before investing $20 in a special WAH pot). I'll report back.
     
  8. David Barnett

    David Barnett Doctor of Teleocity

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    Could the input and output maybe have become connected somehow? Maybe check the wiring to and from the switch, and see if the switch has developed an internal fault?
     
  9. saleake

    saleake Tele-Meister Silver Supporter

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    I just sent my King Vox that I bought in 1972 to a shop in Michigan called Area 51. I’ll let you know when I get it back.
     
  10. NoTeleBob

    NoTeleBob Tele-Meister

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    Good idea, I'll check /bypass the switch into wah mode while I'm in there. It is fine with the the WAH switched out so it's not the jacks.
     
  11. NoTeleBob

    NoTeleBob Tele-Meister

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    Initial testing indicates the pot is bad. I will swap it tomorrow and see where I get.
     
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  12. NoTeleBob

    NoTeleBob Tele-Meister

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    So the pot swap helped, but I still have issues.

    You know that high level hiss you hear with a/any (well working) VOX WAH when the pedal advances to full? Well, I have it but multiplied about 20 times in volume. To the point of becoming almost a staccato buzz. Worse the more pedal you give it, just like the standard hiss, but again, 20x worse. It's like it has it's own gain section. Otherwise the pedal seems to sound normal.

    Ideas?
     
  13. Peegoo

    Peegoo Poster Extraordinaire

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    Closely inspect every solder joint in the pedal (jacks, switch, board) using a bright light and high magnification. They should all be smooth, reflective and silver in color. Re-flow any joints that are dull gray, or that appear to be fractured.

    When re-flowing a joint, use a dot of flux and fresh leaded rosin-core solder. Keep the tip of the stick clean and tinned with fresh solder as you work.
     
  14. NoTeleBob

    NoTeleBob Tele-Meister

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    Thanks, I was planning on going that way.

    It also occurred to me that this seems like a grounding issue. I've done the basic checks on that and it passed. Also, when switched off it passes the signal OK (no bypass on this oldie) so I figured the jacks were OK. But, now I'm suspicious that maybe the ground is marginal and the WAH circuit is magnifying it.

    I'll recheck all that and do some reflowing. Can't hurt!
     
  15. David Barnett

    David Barnett Doctor of Teleocity

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    Another point when re-flowing - the circuit boards in Cry Baby wahs, especially older ones, can be pretty fragile. Work quickly and carefully, especially around the terminal posts.
     
  16. Ringo

    Ringo Poster Extraordinaire

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    Did you clean the input and output jacks? I had an old DOD Flanger years ago that was squealing and making noise, it was dirty jacks.
    Honestly the Crybaby has a pretty simple circuit, some components could go bad I suppose , I have owned quite a few old Crybaby wahs, and I modded most of them to true bypass with a new pot, didn't have any noise or hiss issues.
     
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  17. saleake

    saleake Tele-Meister Silver Supporter

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    Dan Albrecht did a fantastic job rehabbing my 1972 King Vox Wah. I highly recommend him. [email protected]
     
  18. NoTeleBob

    NoTeleBob Tele-Meister

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    Just wanted to follow up on this: Turns out the pot was not the issue. I have swapped the vintage pot back in because vintage.

    It all came down to dirty jack contacts and the jacks not grounding to the chassis properly. I spent some time sanding the contact points, which helped but it was still noisy, intermittent, and hissing treble. I figured I needed new jacks, but as a last ditch I pulled them out an sanded the metal contact surface along with the top of the jacks.

    That did it! Sounds good, nice and smooth. Need to test it into an amp but it sounded great into muy headphone amp.

    I might have gotten away with just loosening and tightening the jack nuts, but I figured that doing it right should set it up for another 40 years of service. I'll likely be dead but someone younger can use it to reproduce 80 year old music only old goats listen to.
     
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