The keypad is worn out!
It is possible to strip these keypads and, using a pencil eraser rub the contacts on the pcb. Also, clean the back of each button.
You WILL trigger the tamper circuit in opening the keypad (enter your code to stop it and when you've completed the job press "reset") Also, make sure you don't short out the power supply to the keypad or you'll blow a fuse in the main panel.
Inglishg, January 2010
