Restoring burglar alarm default codes

[Chris Hogg]

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 process!

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?

[Tim Streater]

D'ye have the engineer manual? That gives a sequence recover to default codes on P25.

[Chris Hogg]

Ah yes. Thanks. Perhaps I should have read through the manual in more detail! When I turn off the mains power and open the control box, am I likely to set off the tamper alarm. I assume the answer is yes, in which case will it be silenced by presenting the tag to the keypad, as it did when I was changing the PIR sensor? And will removing the internal battery stop it from re-occurring while I fiddle with the links on the NVM and kick start pins, do you know? I ask, because I like to know what to expect, even if it isn't welcome.

[Tim Streater]

Umm, can't help, sorry. I don't have the device, I found the manual online is all.

[Chris Hogg]

OK, thanks anyway. I'll expect the worst! Earplugs to the ready!

[Dave Plowman (News)]

I recently fitted a new panel here to replace the 20 year old original. Both reset to defaults if totally powered down. Easy enough to try - although the alarm will obviously sound when you open up the case to disconnect the battery.

But that's not to say there aren't some around that don't.

[Mike Tomlinson]

En el artículo , Chris Hogg escribió:

That feeling of panic as you scramble to get the door open and push the anti-tamper switch inside, then present fob or key in code is awful.

Beware that the bell box might be SCB - i.e. have its own battery, so switching off the power and yanking one of the battery wires off might not shut the external bell/siren up.

[Michael Chare]

Neither the old Karizma, nor my new Texecom Premier Elite lose their settings if powered down.

There was a procedure for clearing just the engineer code in the Karizma. Described in the engineer manual.

[Dave Plowman (News)]

OK. Although I'm not sure there's much point in having the panel retain settings after being totally powered down?

[Andrew Gabriel]

Well, that would be a problem after a long powercut (or a not-so-long powercut if the battery wasn't in good condition, as they often aren't).

[ARW]

And stop alarm companies tying you into a contract.

[Dave Plowman (News)]

Not much point in having an alarm that doesn't work during a power cut? After all a local blackout might be prime time for a burglary?

The SLA one in mine has had a very long life. More than can be said for the Nicad in the bellbox.

[Dave Plowman (News)]

Which of course the majority are. But I was talking about a DIY one.

Also, how to those that do maintain the memory after being totally powered down work? Another on board battery just for that?

[Andrew Gabriel]

Mine uses an EEPROM.

[ARW]

Exacty the same way a car strero remembers the security key code and your stored radio stations when you change a car battery. Non volatile memory.