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Bass registers issue

mgavrilov

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Hello! I've had this issue with my bass registers for a long time, but I decided to try and fix it. So on my Weltmeister Supita sometimes, not always, when I press the registers without basses (the ones that should deactivate the low bass reeds), they don't manage to get deactivated and still continue to sound, as if I hadn't pressed a register that should exclude the bass reeds. So my bass side looks exactly like this: JriTRtJ.jpg

The interesting thing that I found is that if I turn the accordion upside down, this problem dissapears, no matter how many times I try to duplicate the problem, it doesn't work, the right register is activated always in this position. So somehow gravity helps it in the upside down position, and gets in the way of it in the playing position. I disassembled the accordion and tried to see how the orange plastic sliders are moving in there when I press the register buttons in the different positions. But I saw absolutely nothing wrong - no matter the position, playing or upside down, everything seems to move fine and in the absolute same manner. The only manageable thing that I saw in there was this screw:
JriTRtJfd.jpg

I have tightened it a little bit and things seemed to have worsened, so then I unscrewed it a bit and things are somewhat better, but still I don't know when this will happen during a performance (for example I switch registers in Handel's Sarabande from bass to non bass and it doesn't always work, so the whole piece is messed up if this happens 😄). And apart from that, I don't even know if this screw has anything to do with the problem or if it was just a coincidence. It's strange that when this happens, the only way to activate the non bass registers, which are 2, is to press the Master, and then press one of them. And also, when they do manage to get activated, they have to be pressed really hard down, otherwise you can hear some air escaping, along with the sounding tone. It's a relatively minor issue, since it's really a problem only when I'm changing registers during a piece, but anyway, any ideas?

3urI66m.jpg
 
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Sometimes on my older accordion, how I press the shifter makes a difference. I usually try to "slam it home" and this action shifts registers or whatnot effectively. If I only meagerly press the buttons, there is a weird halfway state that can be had and it sounds bad, some notes are off because different valves are only half-closed.

You seem mechanically inclined, a good trait for accordionists, and it seems like you've come to the fore with workarounds and diagnostics. I think you are barking up the right tree. Find the screw position which makes the problem mostly disappear, and be mindful how you press the buttons to switch. Practice enough times to see if there is a pressing force to be avoided.

Analyze the machinations some more, have a glass of wine, think on it, and see if anything pops up. Could it be that the other nuts and washers riding on the same plastic slider are too tight and providing a damping effect to full range of movement of the slider? Everything in there should glide like butter and go the full range of movement to achieve the desired switch in register, right? Keep looking at it, this is what I do when I troubleshoot complex machines (cars, accordions, electronics, etc). Good luck.
 

debra

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This type of mechanism is one of the worst. The plastic is not as rigid as aluminium (used more for such sliders), and it gives more friction. You might try some of that dry lube mentioned earlier in the forums (absolutely no oil) and the bolt that should not be tightened (because then everything freezes up) should be loosened a bit but held in that position with some thread-lock. Generally there are three main problems with register sliders: friction, friction and friction! And that explains why "slamming on the registers" appears to work: you slam on them to overcome static friction (to get the sliders to move) and the faster the move the more chance they will actually move to the end, as dynamic friction is lower.
 

Dingo40

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But slamming increases the stress on the parts and then...?😬
I've had plastic register parts break on my Armando Bugari Ch Cass twice ( first time under warranty, luckily), the second at my own expense. Not cheap! And five months waiting. The parts needed to be sourced from Italy, and that was a whole other experience!😬
None of my pre- seventies accordions have given any hints whatever regarding coupler issues! Not all change is progress!😀
 
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Sebastian Bravo

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italian register mechanism have a kind of spring that holds the plates into the desired position. You should try to imitate that system in your accordion, it would fix the problem forever. Unfortunately, i don't have any italian accordion in my workshop now, so i can't take any photos. But i'm sure another member will know what i'm talking about and be able to take a photo of the spring.

edit: i found it online, but maybe a video of this part in action would be better to give you a good idea
Screenshot_20201218_084009.jpg
 

mgavrilov

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Thank you all for your attention! The community here is really made of good people :) I disassembled the accordion now and looked at it more carefully. What I found is that the screw had nothing to do with the problem. The thing is that the hook of one of the metal levers that control the sliders that get in the reed blocks was disengaging from the plastic slider, controlled by the switch buttons. Here is a picture of it in the normal state:
dsadas.png

And here it is after a bit of pressing of the register buttons:
hgfghjhg.png
hfgnvbnvbn.png

So I had to figure out how to keep them together at all times. I didn't want to take it all apart so the smartest thing that I came up with was to tie the metal lever to the plastic slider with a thread. The strongest thread that I had was a dental floss, so here is the result:
kjhhiuh.png

I finally cut the thread's ends, and now it's working perfectly. I think it will last a long time, let's hope so 😄
 

mgavrilov

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Yes, I don't know why they made the hook so short, it's obvious that at some point in time it will escape the hole. Overall the plastic slide should have been surrounding the hole, like it's in the other slides, and the hook should have been longer. With the thread I have got them close enough so that it can't escape, and we shall see if the solution is permament, or I will have to open it up again some time soon 😄
 
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Thank you all for your attention! The community here is really made of good people :) I disassembled the accordion now and looked at it more carefully. What I found is that the screw had nothing to do with the problem. The thing is that the hook of one of the metal levers that control the sliders that get in the reed blocks was disengaging from the plastic slider, controlled by the switch buttons. Here is a picture of it in the normal state:
dsadas.png

And here it is after a bit of pressing of the register buttons:
hgfghjhg.png
hfgnvbnvbn.png

So I had to figure out how to keep them together at all times. I didn't want to take it all apart so the smartest thing that I came up with was to tie the metal lever to the plastic slider with a thread. The strongest thread that I had was a dental floss, so here is the result:
kjhhiuh.png

I finally cut the thread's ends, and now it's working perfectly. I think it will last a long time, let's hope so 😄
Brilliant! Nice catch.
 

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