Just got done working with a student who is preparing a jazz recital. He moved up to a nicer bass this year, a Shen 180 that is much more worthy of his ability and gives him a better voice. We were working with his amplified sound today and found that one of the tuning pegs (the A string tuner) is rattling on certain sympathetic notes played on the bass, and this rattle is getting amplified. it stops if i hold the tuner lightly while he is playing. I don't know the name of the tuner brand, but they look like this: What strategies are there to quiet down a rattling tuner outside of standing there and holding it?
So if you hold the flat part of the tuner the buzzing stops? A short term solution that my friend used was get a bobby pin and attach it to the tuning peg and kind of make it wedge where the round part is. The long term solution was have someone mold the tuning peg to make it tighter within that small ball (does all that make sense?)
I'm not sure if it is the key part or the corkscrew part rattling - it seems as though holding either stops the sound. I thought maybe there might be a known issue with this model of tuner that someone might know about. I've never had an issue with this on my LaScala plate tuners, but I seem to remember another student having a similar issue years ago with another Shen tuner... or I could be imagining that.
It sounds like the key is a little bit loose in its mount. The solution to that will be tightening the mount on the key. Figuring out how to fix that requires finding whether it's rattling axially or radially, more likely the latter since the string tension is axial at the key. It's also more likely that the rattle is at the rear mount, closer to the key handle. Try stuffing a wad of string or something soft between the key and the pegbox. If that stops it, you probably want to look at acquiring a replacement machine, because the mount bushing is worn or too large to start.
I had the same problem when I bought my upright in December 2016. The luthier came out and put cyanacrolate glue between the the elephant ear/tuning "handle" and shaft that it attaches to. That solved it on the spot, and has solved it every since And I play the instrument every day, and have gigged with it 5 times now. No problems. That might be something to look into. To test it, you could try having one person pluck the strings while someone else really grips the tuner to hold it steady in its post mount. I think that's what the luthier did to isolate the problem.
Very quick 2-min fix.... - loosen that string & make sure screws are tight between a) the plate and the wood, and b) the cog & the tuning post. Retest. - Improv with cork grease or lip balm BETWEEN where the cog surfaces touch to lessen the metal-on-metal rattle being amplified. - lastly, slide a small piece of paper or thin cardboard between the plate and the spiral cog of tuning peg. (Does the same thing as holding it). That settles things quickly most of the time IME. Other fixes can be quite tricky.
A few of solutions come to mind: 1) Make sure that all four of the large machine screws that hold the actual gears in place are finger tight. 2) Switch the E and A gears. Sometimes the wear spots will cancel out any rattling. 3) Make sure that the tuning post has not taken a shot that loosened the attachment of the worm mounts. 4) If nothing else works, contact your dealer or CSC Products to get a replacement. Good luck! Let us know how it turns out.
What seems slightly unusual about this tuner for me is the way the key attaches to the worm. A brass tube is slid over a protruding iron stud, and a pin is hammered in to hold it. See if you can detect any movement in that joint. If so, try removing the tuner, putting a drop of Krazy glue into the joint, and then a hammer blow to the pin. You obviously can't hit it directly with a hammer, so use one of these: In the mean time, how about a rubber band from that shaft over to the one on the D tuner?
Actually, my SB-150 had that issue when I got it (used), but I don't think I posted about it. That's where I got the crazy glue (cyanoacrylate) idea; the luthier I got it from used it.