Tech/maintenance Octave G flat and weak.

[Mix O Lydian]

Yamaha 62 alto. When playing octave G it is coming out flat and weak. It seems to have started in the last two days. Only occurs on octave G.

I play the saxophone daily for at least two hours. This is a mechanical issue. I I know it's not me!

The octave mechanisms on both the body and the neck appear to be doing what they are supposed to do.
What could this be?

 

[Colin the Bear]

Leak at Bis or G#.

 

[Mix O Lydian]

Leak at Bis or G#.

Oooh!
Doesn't sound like something I can fix myself then!

 

[Targa]

Oooh!
Doesn't sound like something I can fix myself then!

It might be. If you stare at the mechanism for long enough you can see how the regulation works and a leak might be as simple as adjusting a screw or adding a bit of cork.
If you think you can see perhaps if a bit of cork being thicker would make the key tighter you can slip a piece of ciggy paper under it and see if it makes a difference.

 

[Mix O Lydian]

I just found this little bit of felt dangling from the G# mechanism. Explain why the fault occured quite quickly. Must have come unstuck. I suspect this is the culprit?

 

[JayeNM]

maybe, maybe not.

Put your finger on the G# cup, press it...does it seem to move the key cup down onto the tonehole or is there no motion at all ?

 

[Stephen Howard]

I just found this little bit of felt dangling from the G# mechanism. Explain why the fault occured quite quickly. Must have come unstuck. I suspect this is the culprit?

It is indeed. It's the buffer felt that sits under the G# arm that sits over the key cup arm (with the cylinder attached to it). Note the wear point in the middle of the piece of felt where it sat over that cylinder.
The fix is...to glue it back on.
Shouldn't be any problems - the bell key table might feel a touch clunky for a while but will settle down once the felt compresses a little.

 

[Colin the Bear]

Take heart that you've come to a point when you know something is amiss and it's not you.

Have a look, now and then, to see how the mechanism works. Don't try to take it all in at one go. Isolate an area and watch how it works.

It's just a tube with holes covered by flaps. Opening them in order, one at a time from the bottom, gives you an ascending chromatic run.

Alternative fingerings often work the same pad by different levers. Do it without playing and watch things move.
It's a very simple system. Lot's of very simple connected systems regulated with bits of cork and felt, that wear or fall off.

 

[Mix O Lydian]

Take heart that you've come to a point when you know something is amiss and it's not you.

Have a look, now and then, to see how the mechanism works. Don't try to take it all in at one go. Isolate an area and watch how it works.

It's just a tube with holes covered by flaps. Opening them in order, one at a time from the bottom, gives you an ascending chromatic run.

Alternative fingerings often work the same pad by different levers. Do it without playing and watch things move.
It's a very simple system. Lot's of very simple connected systems regulated with bits of cork and felt, that wear or fall off.

I'm amazed that I'm now able to diagnose and even fix faults like this. I just don't know what all the different parts are called. On this occasion I'm taking it to a tech today and they can have a general look at the sax after they put a new pad on for me.