| Author |
Topic: grounding problem on Supro |
Paul Sutherland
From:
Placerville, California
|
Posted 11 Nov 2013 5:39 pm |
|
Recently my Supro volume pot has been shorting and otherwise acting erratic. The pot is more than sixty years old so I decided I had to replace it. The steel was becoming unacceptable for professional use.
I had a new 250K Allen Bradley pot sitting around so I decided to make the switch and started soldering. I've spent all day trying to make this work properly. I've re-soldered connections multiple times and always the same result.
The problem is the steel is fairly quiet when I'm not touching it, but the moment I put my hands on the strings or the pickup it starts buzzing. It's not a real loud buzz, but it's noticeable to me.
Also, the tone pot, which I never use, now has a tremendous buzz when I start to back down the tone knob, and then shuts the guitar totally off when the tone knob is turned fully counter-clockwise. This is less of an issue to me because I leave the tone control set on full treble (full clockwise position.) In fact, I don't even have a knob on the tone pot stem. I'd just as soon remove the tone pot circuit entirely, but I tried that and the steel buzzed like crazy, so I put it back in for now.
This sounds like a grounding problem, but I can't see how I failed to reconnect everything just as it was before I removed the old pot.
Any suggestions and comments are welcomed. |
|
|
|
Tom Pettingill
From:
California, USA (deceased)
|
|
|
|
Paul Sutherland
From:
Placerville, California
|
Posted 11 Nov 2013 7:44 pm
|
|
| Thanks Tom. That's most helpful. Interestingly, that's not how my components were wired. I'll give this a try in the morning. |
|
|
|
Paul Sutherland
From:
Placerville, California
|
Posted 11 Nov 2013 9:53 pm
|
|
I went ahead and re-soldered per the diagram and it works. Imagine that! I also took out the tone circuit and the steel works just fine without it.
I'll, of course, keep all the original components. But for right now I need a functioning lap steel and this thing meets my needs with no need for a tone control.
I use this steel for screaming blues, rock licks with an overdrive pedal. I feel a bit guilty in admitted that, but I get lots of favorable comments from band-mates and the public. |
|
|
|
Peter Jacobs
From:
Northern Virginia
|
Posted 12 Nov 2013 5:56 am
|
|
Thanks for posting that diagram, Tom. I hadn't seen it before, and it's good info to hang onto.
I noticed on my 1964 Supro Jet Airliner that even though it is very quiet (as it should be, with the split pickup), there is a tiny bit of ground hum/buzz and no wire to the bridge.
I didn't think it would be necessary, since the pickup sits in the bridgeplate, but I tested it with a wire from pot casing to the bridge, and the last bit of buzz was completely gone. Has anyone else seen this?
_________________
Peter
---------
www.splinterville.com
YouTube: https://www.youtube.com/@splinterville6278/videos |
|
|
|
