Where should I look for the solution?
As I play with the octave key depressed descending from high C, B, A, G, F, E, to lower D and then C, when I reach the D and C, the alto saxophone outputs A and G again! I'm new to saxophone, and don't even know where to look for the cause of this 'problem'.
Please don't reflexively tell me to take it to a shop. I can't afford to do that. I looked at those service prices they are out of the question. I picked up this Buechner sax for $75 and even that was a hit to the budget.
I have a workspace and a lot of tools and would prefer to try to resolve this myself, but the saxophone looks fine. It appears that all the valves/holes open and close properly. It plays well in the mid- and lower range. Thus far, I've only run into the odd response of the D and C keys at the low end when the octave key is depressed.
I'd greatly appreciate any hints or clues or points in the direction of possible issues that might be offered. Thanks!