Crucianelli Bass Coupler

[boxplayer4000]

This is a 4/5voice accordion from the 70’s. The bass couplers have come under a bit of strain and the coupler button on the left is seized as well as its part inside which should rotate. There’s no obvious way I can see to remove the button and I’d be interested in any opinions on the matter. I’ve already applied a limited amount of release fluid.

 

[debra]

It's a bit of a detective puzzle to find out where a register mechanism starts offering resistance...
The first thing to try is to remove the reed blocks to see if that helps. If they are too tightly fixed in place they may press down on the soundboard just enough to cause friction in the sliders.
But... some more disassembly may be required to find the culprit. Try to avoid using any lubrication anywhere though. A register mechanism should work effortlessly without any need for lubrication.

 

[boxplayer4000]

Paul, thanks for that.
The coupler slides are free.
The problem is the coupler button, which is hinged on its upper edge, and the small semi-rotating piece it activates are seized solid.

 

[debra]

Paul, thanks for that.
The coupler slides are free.
The problem is the coupler button, which is hinged on its upper edge, and the small semi-rotating piece it activates are seized solid.

Could be the result from impact force, maybe?
Best of luck trying to disassemble the mechanism.

 

[boxplayer4000]

The lever mechanism behind the coupler and under the selector slides could only have been accessed before the bass buttons were put in place, during initial assembly. The accordion is midied so further access problems.
I have managed to get 4 of the 5 couplers to work; the one at the top is a 'mute' coupler.