We need to change the code on our present system (OPTIMA XL) as one of the digits we use is no longer working .It was installed 13 yrs ago when the house was being built, but as usual, through the years we have lost the original instructions. Can anyone help
You may have a problem there. In most cases, you will need to input the original code before changing it anyway. Since the switch doesn't work it's catch 22.
Phone a few small local tv repair companies to see if they can replace the switch for you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix home alarm systems.