Hello: I have a Yamaha Allegro open hole flute. I put plugs in the holes and all the sudden one of the keys is out of adjustment and isn`t moving freely. I`ve tried to adjust every screw I can find and no springs have sprung. All I did was turn the screws (on everything eventually) and I still can`t get it to work. Is there a secret to screw adjustment (keys open, keys closed, a combination?). I have two flutes and I just paid money to have one adjusted. I really don`t want to pay $20 everytime a screw comes loose. Any suggestions?