Hi to all

I recently stumbled upon a Kawai CA500 digital piano which is available for others to play in some semi-public space. Unfortunately there are a few keys which are sticking up out of the keyboard. I think it may be some mechanical problem which could potentially be fixed if I could open the keyboard and see what is amiss. The issue must be somewhere not in the front part of the keyboard (where the keys are visible from above) but in the rear part which is concealed by the electronics and the sliding cover (actually the cover even hits the sticking key and the key needs to be pressed to let the cover pass through).

My question is then - is somebody here familiar with that particular piano model and could tell me the easiest way to open it and get access to the rear part of the keyboard? I mean which set of screws and wires to remove and in which order (I can of course experiment by trial and error by though it would be better to ask - it is not obvious at first glance). I have another Kawai model at home (newer) and in that case it was very easy to get to the keyboard mechanics when I needed, but for this model it seems to be trickier because everything is concealed behind the electronics as far as I can see.

Just as a note - I know that the correct procedure is to take it to a certified technician and there are warranty issues etc but believe me this is not really the way to go in this case.