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Being a helicon, my guess it has the "watch spring" buttons plus S-arm linkage. These can bind and hang up either on the spring or at any of the several points along the linkage. Even on a "modern" linkage like my Miraphone, and mine is old enough to have S-arms, but the regular springs and paddles, my 1st valve was hanging, so I had the tech remove it, thinking it must be full of gunk. The rotor was clean, the linkage was gunked.

also, you might try cleaning and oiling the linkage. this helps too. Also...as far as mirafone valves go...My valves started to hang up. so, i did a combination of things. one is to loosen the back valve caps just a little. The second is...my first valve would hang up bad, so i took the internal cover (between the cap and the valve) out and it work flawlessly. then a couple months ago it did it again so i put it back in and its been working ever since. I find that rotors are "picky" and sometimes you just gotta mess with them (cleaning, loosening caps etc.) a little bit and they'll be fine.

Ben...

I had trouble with rotary valves on a fairly new Miraphone 182.

Turns out I was getting so excited about playing that I grabbed the 1st and 3rd tuning slides hard enough to pull the slightly out of line where they connect with the valves... situation was temporarily relieved by exerting a little pressure the other way. Was permanently relieved by have the repair guy solder in some new supports.

The timing of your events seems like what I experienced.

John

On some of these old horns, things get worn enough that surfaces that aren't supposed to rub do.

Check to see if the bottom of the stop arm is rubbing against the top of the top bearing. Normally, there's a small gap (the rotor shaft is tapered), but an over-eager tightening up of the stoparm screw can gum things up.

If it appears to be the case, try unscrewing the stop arm screw about a quarter turn to free it, then tap on the head of the screw with the handle of your screwdriver to loosen the stop arm a bit. Check the operation. If it's okay (not binding), the "quick and dirty" fix is to insert a thin shim in the stop arm shaft hole. That may or may not make for a noisy rotor--if it does, you're probably going to need to have the valve bearings "swedged" by your repair tech.

Just a thought....

ben wrote:Many thanks for all of the advice! I was out of town this weekend, and am currently away from the horn. I'm hoping to have some time to examine it more closely tonight, and I'll post if i can get it working , or if I have to throw in the towel and call for the experts , but if they can fix it, I'll be estatic

When all else fails, let a piano tech. fix it

Sheesh, you're only a couple hours away from Dan "Tuba TInker" Schultz down there in the Evansville area.

Eric "a former Hoosier who would probably bug Dan several times a year if he lived within a few hours' drive" L.

When all else fails, try running ice water through the horn. Sometimes the heat of playing swells the rotor and it drags on the side of the casing.

ben wrote:Its a 6+ hour round trip, and I don't have the time to make that commitment and have it before August 3rd (CD Release surprise... oops, just blew that one).

So throw it on a Greyhound bus (Greyhound Package Express). It should get there in one or two days...

Eric "trying to help" L.

Roger Lewis recommends sewing machine oil for the top & bottom rotor bearings, and 3-in-1 oil for the linkage.