John, thanks for your advice but since I have been the guinea pig by using the contact spray, I will keep you and others informed if I have any future problem. Right now, with spraying the buttons that were not working well and the keys that I sprayed, I couldn't be happier. With the results, I feel I have saved an expensive service by hoping a service technician could both replace the buttons and solve the clicking in the keys. As I said in my earlier post about the Sequencer/Reset button and the Stop/Start button not working well, they work perfectly now after using this spray.
Mark