I've run out of places to find an answer to a problem so hopefully someone here can help.

I have a Ness D8 home security system which is about 11 years old. For a couple of years now and again (usually months) the panel buttons don't respond when trying to disarm. They are lit but don't respond, obviously resulting in the alarm going off. Sometimes if you keep putting the code in repeatedly is suddenly works again. It's become more frequent and certainly more frustrating to a point were we're not arming it.

Ness had no idea what the problem was, the company I called out had no idea suggesting it could be the mother board and they'll be in touch (they havn't been yet).

Its not the mains or battery. Its also not monitored. Not sure if its the keypad itself but every key does not work, not just the odd key. Anybody have any idea what the problem might be.