apple Lisa2. Any advice on non-working floppy drives?

I think this thing uses the well-known Keytonics cpacitive keyboard.The foam pads under the keys can fail with age (resultign in non-working keys), also the metalising on the back of the lower plasic disk can vanish (!). One of the lisa manuals implies that the keyboard has 3 conenctiosn back to the main unit : +5V, ground, signal. I have no idea if the signal line is bidirecitoanl or not, I susepct it isn't. In any case, if you put a logic probe on the signal line, what is it doing? Does it do anything if you press a key? These keybaords will come apart. After removing the outer casing, flip the keyboard over and take out all the small screws that hold the PCB to the keyframe. Then lift off the PCB. You cna now inspect the foam, etc. -tony