Rotary valve troubleshooting

[bort]

Here's what happens:

Horn laying down on its side., rotary valves are silent.
Horn in playing position, 3rd valve goes clack clack clack. Sounds like the end of the linkage on the valve side. It is new Minibal linkage.

Already oiled all of the usual places with no real improvement. No play in the linkages and bumpers are new. Something definitely isn't quite right, but I ran out of ideas.

Any ideas for what to check?

[bort]

Thanks guys! It won't be until tomorrow that I can revisit this... but I will check it out the vertical play.

[Matt Walters]

Bort,
If #3 and #4 rotors go the opposite direction from #1 and #2 rotors, then I suspect the answer is the linkage gets pulled down when you put the tuba in a playing position. If so, the minibal can hit the stop arm when you use real world pressure. If I am right, you'll need to adjust (bend) the linkage. This is one of the things I often have to fix before I ship out a Chinese made rotor tuba.

[bort]

Thanks Matt! Hoping it's not that, but will certainly put it on the list to check out.

One other thing -- when I bought the tuba, the previous owner (a repairman that people know and trust, and he's around here from time to time) put this black shrink tubing on the linkage. I thought it was just cosmetic, so I took the tubing off a little while ago. Might just be a coincidence.



I'm hoping that Joe's first thought is what's happening. If so, that would make sense. Since I bought this horn, it's been transported probably close to 3,000 miles in the back of van or trunk of a car. Things tend to wiggle themselves loose after a while, and that probably speeds up the process a little bit.

Will see what I can do this morning, then post about it.

Thanks again!

[bort]

I checked this out yesterday... Oiled the horn before I tried anything, and all is back to normal. I cant find any play at all in the valve, so it must have been something else?

So there are two solutions to most tuba problems -- more air, and more oil.