What to do with a Miraphone 186CC

ai698 · Post by **ai698** » Sun Oct 08, 2006 10:19 pm

Here's the tuba in question-

ai698 · Post by **ai698** » Sun Oct 08, 2006 11:32 pm

Chuck(G) wrote:I believe that you can order new DVS parts directly from the factory--search the Tubenet archives. But your noise may not be the DVS setup but normal bearing wear. Or, possibly, some idiot disassembled the valves and didn't seat the rear bearing plates all the way.

What happens is that some bearing play develops and the rotor rattles when it's either accelerated from a stop or when it stops when hitting the bumper.

Unscrew the rear caps and make sure that the bearing plates have been seated "home'--that is, the bearing plate surface should be flush with the edge of the casing, not sitting above it. Using a wooden dowel and a small hammer (like the handle of a screwdriver), you can re-seat the bearing plate home--small taps on the dowel resting on the bearing plate, moving the dowel around and around the edge of the bearing plate until it's seated flush.

If the bearing plates are seated and you still have rattling, you should schedule some time with the local repair tech so he can "swedge" the rotor bearings.

A stopgap measure is to take up any end play with the setscrews in the center of the rear valve caps (many Miraphones have thse). Turn the setscrew bit by bit clockwise until the rotor becomes sluggish, then back off a smidge. This isn't a permanent repair, but it will quiet things down until you can get the horn to a repair tech.

I was the last "idiot" to mess with the valves when the noise started up over a year ago. I just checked and tightened and retightened everything. The plastic linkage is pretty chewed up, the bottom plates keep loosening when hammering them down, after tightening the bottom screws, the rotors don't have any up and down play. All things considered, it would make great castanets for Carmen Suite. I'm willing to pay to fix this horn, but I don't want to mess with boxing it up and shipping it to the east or west coast.

Chuck(G) · Post by **Chuck(G)** » Mon Oct 09, 2006 12:08 am

ai698 wrote:I was the last "idiot" to mess with the valves when the noise started up over a year ago. I just checked and tightened and retightened everything. The plastic linkage is pretty chewed up, the bottom plates keep loosening when hammering them down, after tightening the bottom screws, the rotors don't have any up and down play.

I'll say again that I don't think it's the DVS linkage. How about the side-to-side play of the rotors?

Almost any repair shop that deals with (French) horns can give you an honest assessment of what's going on. If really is the DVS parts, new ones can be ordered.

ai698 · Post by **ai698** » Mon Oct 09, 2006 12:15 am

It's loose but not too bad. I think it's just a 25 year old tuba that needs work. I'm going to try our local repair person. If she can't do it, then I'll take it to El Paso, if there are any music stores left after Brook Mays debacle.

Dan Schultz · Post by **Dan Schultz** » Mon Oct 09, 2006 1:07 am

ASTuba wrote:
TubaTinker wrote:Check the end play in your rotors, make sure the stop plates aren't loose, and see that the screws holding the stop arms are tight before you waste a lot of time on the linkage. If your linkage is just plain worn out, DuBro links, a few pieces of 4-40 threaded rod, and a couple of pieces of 5/32" ID brass tubing will solve the problems with noisy linkage.
It's a DVS linked tuba. If he wants to do all that, he's going to have to order new parts from Miraphone, as the stop arms and everything on that are different....

Let me know if you need any help.

Hey, Andy... I've done several conversions on these horns! It's just a simple matter of adding a bit of height to the spot on the stop arm where the ball mounts on the rotor arm. Those newer balls are the worst thing Mirafone ever came up with. Why replace old junk with new junk?!