This article deals with keys that behave mechanically differently from other keys. If a key doesn't feel different but shows irregularities regarding how it controls sound, then please check this article instead: Some of Osmose's keys react differently to pitch bends or pressure than others
Mechanical problems with single keys may include a key not or only slowly reverting to the same level as other keys and generally not offering the same smooth, progressive playing feel when pressed or bent. The first thing to verify in these cases is that the key sits correctly on top of its silicon cylinder. It's done by removing and re-adding the cylinder support cassette below the concerned octave to see if the action behaves better afterward.
🪛 You will neead a Torx/6lobe/starhead screwdriver size 10 for the following steps.
1. Turn the instrument over on a soft surface, e.g. a sofa, and loosen the five or six screws of the concerned cylinder support cassette. There is one such cassette under each octave. The image below shows the cassette of the highest octave, which features 13 instead of 12 keys.
2. This is what the removed Cylinder Support looks like:
3. Usually, it is enough to just screw the cassette back in (step 4), but you may also want to swap two cylinders with each other for further analysis/troubleshooting. If you have a single key that is misbehaving, and moving its cylinder to a different position makes the problem move as well, then it means that the silicon cylinder is causing the problem and needs to be replaced, also see The highest or lowest key of my Osmose is sitting too low and feels softer than the rest. Be aware that the cylinders for black and white keys have different shapes, so only those two types are swappable among each other. Cylinders are removed by pulling them horizontally from their rails, see the picture below of a slightly removed cylinder:
4. When all cylinders are firmly seated in their positions, screw the cassette back in. Ensure the keys are not pressed when you put the cassette back in. To achieve this, you may want to lift the instrument slightly with your other hand while screwing in the cassette. This will ensure that the small depression on the top of the cylinders touches the keys in the correct place from below.
If the problem with the key wasn't rectified by ensuring the correct placement of the cylinders, then please get in touch with our Osmose tech support.