My late mother's property has a burglar alarm system, a Scantronic
9651, installed around 1993. Just recently, one of the PIR sensors
started giving false alerts and needed replacing. I have both user and
installation manuals. While it's possible quite easily to tell the
system to ignore signals from any particular sensor, which I had done,
all the sensors are on a single anti-tamper loop. To temporarily
disable this loop, it is necessary to put the system into what is
variously called 'programming mode', 'engineer mode' or 'installer
mode'. This is done by inputting 0 into the keypad, followed by the
default code 7890. Unfortunately, in my case the system doesn't
recognise that code. I assume that on installation, the engineer
changed it from the default to another number.
I did eventually change the PIR sensor, but it was a very noisy
But the system is due to be changed and extended in the medium term.
Is there a way of returning that code (and probably all the others at
the same time), to its default value, for example by powering down the
system and removing the batteries? Or is the memory non-volatile, and
am I stuffed?