I could not find a simple diagram of how the accordion button bass works and I think the world need one

[Harry]

Thanks to a lot of help here, I was able to fix a sticky bass note problem. My first repair ever! Youtube showed me the way into the box and would have been enough if a button was stuck down.

I had to go deeper, mostly blind and reverse engineer the mechanism. Which is hard in an instrument with 120 buttons!

Today I made a quick, not totally accurate! 3d model of what I think is going on. I would like to know if this makes any sense and if folks think it is helpful. I'm trying to show that when the button is pushed, one pallet is opened. If I stay interested, I can animate this and add more bits to show a chord where one button opens 3 pallets.

 

[debra]

I have never seen a diagram. As an amateur (but trained) repairer I have learned mainly from disassembling and reassembling different mechanisms. (There are several different mechanisms, from different brands and periods.) Finding problems with a bass mechanism can be a bit of a puzzle, but you generally get better with experience.
A physically (gemetrically) accurate diagram would be a challenge as every manufacturer assembles bass mechanisms by hand, and bends leves and pistons as needed to make everything work smoothly. So every bass mechanism is just slightly different, even between different accordion of the same model and brand.
Functional schematics would be useful but then to use them requires the ability to see beyond the differences between the drawings and the actual mechanism. But that is what diagrams are for.

 

[AndyM]

Here's one I found a while ago, showing a Scandalli Polifonico 96T, apparently. Have to use a bit of imagination to turn a 2D image into 3D.

 

[boxplayer4000]

If that's the bass button on the top right of the picture I think the lug on the blue bass piston should be on top of the white(ish) lever.
I'm a geek for technical drawings too. However it will be hard to show in a simple diagram how a combination of button force, spring force, mechanical advantage lost/or gained by levers and air pressure on the palette itself combine to make such a simple but finely balanced mechanism.

 

[tcabot]

Very impressive 3d modelling skills...

But maybe just take it apart and see what's inside?

 

[Harry]

I just managed to fix one of these not knowing anything to start, and all I could find were images and videos that had all this STUFF! In the vids they might try to zoom into the mechanism, but that did not help much.

There are endless books, videos, classes, simplified animations on how the basic 4 cycle gas engine works, not to mention I can just bring my car into the local mechanic for repair or professional advice.

It helps me to have the big picture of how something works before I go tearing into it, and that is what I am trying to do with this model. (Thanks boxplayer for the correction)

https://youtu.be/0zMzRyPq4rU

 

[Harry]

I've gotten back to my model. This one is a bit better than the first.