Command 8 some faders stick

[kaioflex]

Hi C8 users,

since a few weeks three faders of my command8 do not work properly. One of them is simply not moving, but struggling with the motor (you hear it well). The other two stick while moving and jump to some positions even I draw a smooth automation curve.
I already used a compressed air spray can to clean the faders from dirt, but it did not help at all.
Any suggestions what I could try to make it work again?

Thanks in advance.
k