I'm hoping someone on this forum can help with a tone/vol schematic for my MOTS supro lapsteel. I know how conventional guitar systems are wired, but when I opened up the Supro it didn't conform to any schematic I'd seen, and the volume pot seems to work as a tone pot, whilst the tone does nothing. The soldering all looks original oddly enough. Any help appreciated. I love the sound of this little 'plank' but would like to get the controls working as they should. By the way, thanks for the advice on strings, Michael.
Glad it's of use to you, yea it's a great blog! I found the section on rebuilding the pickup assembly really good, it shows clearly the design and construction of these unique pickups and the photos are the best I've seen!
I've got a '49 Supro that is giving me fits trying to get it up and running again. I sold it to a guy 25 years ago. He passed and his wife was going to trash the guitar because it didn't work. Lord only knows what he did to it. I have a posting in a different part of this site, but so far I haven't found any solution. The man trying to help is a little too technical for me. Perhaps if I could see a photo, I could fix my problem. This is what I've got to work with. There is only one wire coming out of the pickup. The other is grounded to the plate everything is mounted on via a soldered lug.
It used to hum horribly. I grounded what I thought was the tone pot, (the non Allen Bradley) and the humming has stopped, but so has any signal from the pickup. I have nothing at all now.
Last Edit: May 19, 2013 15:57:12 GMT by willarnold
Post by Colin McCubbin on May 19, 2013 19:24:53 GMT
It is hard to see from your picture, but you need the wire from the PU to go to one end of the vol pot, the other end of the pot should be common ground.
The Cap goes from the same end of the vol pot as the PU input and goes to one end of the tone pot, the center pin of the tone pot should go to ground. The other end of the tone pot goes nowhere (is not connected)
Finally the output to the jack socket comes from the center pin of the vol pot.
(it is possible that the wax electrolyte (insulation) in the capacitor has dried out and shorted the foil plates together. I'd first wire just the volume pot in as described above, with NO capacitor, so you can see if the pickup and vol control work, then add the capacitor and it's pot..) Try this: