I have a Gardtec 800 alarm system. I am in possession of the engineers code. We have the Fb fault showing. I have replaced the battery with a pukka Yuasa one and reset the system but the Fb fault still shows. Also checking the 7 year old Yuasa battery I took out it still shows a good 14/15 volts. I assume the fuse has gone and that the battery was OK anyway. Any help where I might find the fuse or advice on what else it could be would be greatly appreciated!