Simon wrote:
Hello -

My fairly elderly parents have a fairly elderly alarm system. They are
currently being charged about £25 per month by a maintenance company, and
I'd like to know how easy it would be to do the maintenance myself. FWIW,
they already have several noisy dogs and live in a safe area, so I'm not
sure this thing is worth the cost of the contract. The user manual
identifies it as an Anglian "Defender 3000", but this doesn't generate any
hits in Google; presumably it's a rebadged version of a better known model.

The supplied manuals are very basic and don't even tell you how to change
the batteries in the wireless sensors without setting it off, ensuring a
reliable revenue stream for the maintenance company. There's a picture of it
he http://i12.tinypic.com/490cq5x.jpg

Any ideas on what it is and how I perform basic maintenance?
I had a dead battery, and having been quoted 89 quid for an annual
maintenance contract that appeared to do absolutely nothing, I changed
them myself. Alarm system was something predating ADT, from about 1980.
Not wireless, needless to say.

I made sure it was a dry day, when climbing a ladder to smash the
bejeezus out of the bell box would be a viable option if it all went
pear-shaped.

If any neighbours have small children, make sure they are not asleep.
Insert earplugs.
Turn off power supply to alarm. If that causes the external sounder to
go off, the battery on the internal box is dead. Since your low battery
lightis not showing, I'm presuming the battery is not dead.
Open up the internal box.
Figure out where the tamper switch is.

You have two options:
a) Turn the power back on, press tamper switch, enter alarm code (errr,
can't see how you do this using the front panel, is there a fob?)
Everything should now be silent. If you electrocute yourself doing this,
it isn't my fault, and you'll need to be able to do everything else one
handed, as you'll be pressing the tamper switch in with one hand.

b) Work with the external siren going.

Swap the batteries over. You may, of course, now find that the internal
siren goes off. If it doesn't, it will when you close the box, as you'll
need to release the tamper switch... That's why you need earplugs.

In my case, I changed the batteries, and still had an alarm system that
triggered in a powercut. It turned out that there were a couple of fuses
on the PCB, one of which had blown. These were both standard 1A, and
easily changed.

Dispose of the old battery in an appropriate manner.

For 25 quid a month, you could just buy a new wireless system every year.

Ben