I have recently serviced my dx7 and noticed 2 things.
After button replacement, it’s still doesnt work (sometimes works if you lift the panel) [button no. 25]
On the keybed there seems to be a residue/lubricant that goes on a plastic part underneath the key, which im assuming lets the keys move smoothly and without tear to the plastic. What is it?
I used some vaseline to coat each one…and also replaced the damper felt strips.
I’ve checked on the container and it looks like Vaseline but it says silicone…used for scuba gear and rubber lube…
the buttons are a sealed design on the DX7 and there should be no lubricant needed to make them work. I agree with ThatArpGuy that something is out of alignment. Clean that gunk off and investigate why the board does not line up with the exterior panel.