TubeNet

The no name tuba that I'm playing has some unique rattling/vibrations that I think is coming from multiple sources. I hear/feel them during certain fingerings/pitches that I try to diagnose while playing, but can't replicate while feeling around with my left hand. The paddle assembly has movement up/down with some of the paddles where they rotate. Should there be play or does it need tweaking to tighten them up? The next issue is on the first rotor, the bumper plate, screwed into the top of the rotor housing has one stripped screw and I don't have the courage to crank down the other risking stripping it as well. I'm assuming its already been re-tapped to larger screws since they're bigger than the others. Can these be filled and re-tapped or is it valve replacement surgery for the tuba? Any help is appreciated.
Thanks
Joel

There should be minimal 'play' in all parts of a rotor assembly. All screws should be tight. That stop plate screw that's stripped out needs to be fixed to insure that the rotor plate is mounted solidly. That can be a tricky fix. Better take the horn to a REAL tuba doctor.

Thanks bloke and tubatinker. I'll contact Lee Stofer as he is the closest to me (4 hours) and have him take a look at it.