how do i replace a battery pack in an 9540'thats not worked for a few years i am a new owner of the property so wont know the old owners code, old code so how can i overide the old code and how do I disconnect the battery safely? downloaded onstructions to this alarm have followed all the engineers codes factory default nothings Happened, no sound, no flashing of lights opened up the panel with a sceprewdrivee found instructions behind the wires cant reach them battery looks dead anyone help please?

Gemini54, February 2016

no place behind the pcb since its on the lid,so forget that one
all you do is remove the one screw that holds the lid closed,open the unit,remove the 2.1 or 1,9 battery then refit new one be carefull you put red to red black to black close lid key in your pin number to reset

gts, February 2016

Come on, they were put there so must come out.

Behind the PCB is a usual place to find the Inst.

x, February 2016