Vintage Wah Issue

[messenger]

I picked up a vintage Thomas Organ wah yesterday for cheap. It sounded fantastic for about 5 min. Then it stopped “wah”ing. Just sounds like a low pass filter. Won’t sweep. Just stays basically like toe up position. I put my DMM on the pot and it tests ok. Any suggestions?

 

[Kapo_Polenton]

I'd say that pot itself could be gonzo. Or a loose solder connection to it. Start there. It still makes a heel down sound right? Meaning it just isn't going back the other way. Maybe when it heats up from use it is just failing like a guitar pot would over time. It will still measure something but likely won't sweep. Can you play with the sweep and test the pot in diff positions? It should in theory have a diff reading. If it doesn't well..... maybe a 15$ fix.

Cool looking little piece of mojo there though! Get it back up and working and rock some Schenker. No Kirks allowed.

 

[messenger]

I Put a DMM on it and the pot tests fine. When I move the pot it changes value on the meter from 0-98k (or something like that) Someone told me they had a similar issue and said theirs was the 3.9uf cap.

I'd say that pot itself could be gonzo. Or a loose solder connection to it. Start there. It still makes a heel down sound right? Meaning it just isn't going back the other way. Maybe when it heats up from use it is just failing like a guitar pot would over time. It will still measure something but likely won't sweep. Can you play with the sweep and test the pot in diff positions? It should in theory have a diff reading. If it doesn't well..... maybe a 15$ fix.

Cool looking little piece of mojo there though! Get it back up and working and rock some Schenker. No Kirks allowed.

 

[messenger]

It was the 3.9uf cap (the one right below the inductor). Changed it with a 4.7 and it’s up and running. Using it tomorrow at our gig.

 

[psychodave]

Glad to see you fixed it. Try to source an original cap… it will likely sound different with the different type and value cap you are now using.