Hi, I'm a high school student with a small amount of instrument repair experience.
Last week, one of my friend's marching flute started acting during rehearsal. It's an Armstrong flute with an inline G. When playing the long Bb with the 1&1 fingering, the A key would also come down.
I immediately thought it was just rust/dirt/grime in the rod itself because of humid and hot midwest weather. I didn't address the issue directly but instead did a full COA. I took it apart, dipped the flute body in a tarnish remover, replaced HJ cork, cleaned all the rods, and replaced two pads. I put the entire instrument back together and oiled/adjusted the mechanism. Flute played perfectly when I handed it back to her.
About 2 weeks later during rehearsal, the same issue is occurring. The F key is pressing down the Bb pad and A key. I only have about 15 minutes to try and fix it before rehearsal on Tuesday morning. Any ideas of the what the issue could be?
If it doesn't need more oil, I'm guessing the rod is bent. If it were bent, how could I straighten it? Just use my hands? More key oil?
What other problems could cause this?
Would appreciate any help.