Conn 88H Trigger Linkage

[Mamaposaune]

I have a high school student with a Conn 88H, not sure of the vintage but it is probably less than 20 years old. (He bought it used.)
He is having intermittent problems with the trigger/rotor that I cannot figure out. He is pretty good about remembering to oil it, and I have also oiled it during lessons when it is acting up (down the tubing and both spindles) but it does not seem to be the rotor itself, as it can be turned easily when holding the piece close to the rotor. I should add that it is mechanical, not the string type, and not adjustable.
The trigger lever, where his thumb goes, has some play in it but does not have a phillipshead or straight screw that can be tightened - they look more like rivets. (Sorry, probably not quite using the correct terms)
Anyway, it feels to me as if the trigger linkage itself, or just the loose thumb lever, is binding and is the source of the problem.
Any thoughts on this? We are about an hour from Dillon's, where he bought the horn from, but the family seems to be very busy and I don't see them making a trip up there anytime soon.

[harrisonreed]

If the trigger is out of alignment or loose in the saddle that holds it, it can shift the force put into the linkage. If it is going in at a 90⁰ angle into the ball joint, rather than basically any other angle, this can cause it to bind at the joint.

Have you used a heavy oil on the joint?

[Mamaposaune]

I'm not sure of he has the heavier oil at home, it gets Al Cass from me because that is what I happen to have in my studio. I can bring my heavier oil to the next lesson.
I think you are confirming what I am seeing with the linkage, but does it require a trip to Dillon's repair department for a fix?

[harrisonreed]

There's gotta be a closer tech than that, if you can't tighten up the lever yourself. Should be a very easy fix for any shop

[NotSkilledHere]

I was getting a few things done at Houghton Horns and someone had a similar issue with their french horn on one of the rotors/triggers. In her case, it appeared that she used natural oil to help oil the linkage and Houghton had used synthetic oils after they deep cleaned the horn for her. When you mix synthetic and natural oils, it kind of becomes gunky and glue-like. they cleaned the horn again and remembered to get together with her on what kind of oil she was going to use before relubing everything again.

I'm not sure if your student is in the same boat, but it might be worth taking a look at his oil and past oil and seeing if he managed to mix synthetic and natural oils. just thought this might help a little bit even though it may or may not be a similar situation