Many has written here about this problem.
After many trials and discussions with other users I advise the following:
1. If your S.N. is CNA 42... or higher you should not have a hardware problem and could go to 3. But in any case better try this:
2. Turn the key click on and press very gently and slowly all the keys. If some key fail ... return the unit.
3. If the above test is successful and you have the ROM version 1.23 TURN THE CLOCK OFF (clear flag 40). It seems to solve the problem. And then wait patiently the new ROM relase to turn the clock on.
Edited: 2 Nov 2004, 3:50 p.m.