Hello. Don't know if this is in the right section, Just joined the forum.
I have what I think is a Gardtec 800 series alarm. Its been here since we moved here 22 years ago so obviously quite old. Lately its been playing up where you set the alarm. Go upstairs to bed and 30 seconds later instead of hearing the beep of it being set the alarm goes off instead. We had a power cut the other day and since then its been happening all the time but Im pretty sure it was happening on occasion before that.
Any ideas or do I need to call in a professional? Happy to do that but just thought it might be something simple.