Scantronic 9800 intruder alarm. Help on how to disconnect it please

[New Tes]

We have had this alarm for over 25 years and have had it serviced every year. This time when the engineer came out he was unable to get into engineer mode and could not clear a tamper on our zone 6. He said the microprocessor was 'fried' and that we need a new system. My problem is that he left without disconnecting the alarm and we are worried that if we try to cut the power the internal and external alarms will go off with no way of turning them off that we know of.
Can anyone give us some advice as to what to do. We are pensioners and cannot really afford to pay £120 per hour for a call out. We are not particularly technically minded but are sure that we will be able to disconnect wires in the control box if that is what is needed. We just don't know which ones.
thank you

 

[sparkymarka]

To be honest the service engineer should have down powered the system for you , I very much doubt the panel is fried more than likely one of the keys on the keypad is not working , without knowing what bellbox you have can’t say if the bell would stop after 20 mins
But normally pull fuse at the side of the control panel , disconnect the internal battery, wait 20 mins for the bell to stop or get ladders out

 

[New Tes]

Thank you for your prompt reply. We will try this and hope that the alarm stops after 20 minutes because our neighbour has has some building work done which means we can't set up ladders. There is a wire that goes to the outside alarm in the bedroom on the other side of the wall. Would it be safe to cut that and could it stop the alarm that way instead?

 

[sparkymarka]

No ....worst thing you could do ...

 

[New Tes]

Sorry I wasn't very clear. I meant that having pulled the fuse and disconnected the battery if the external alarm didn't stop could we cut the wire? If this is not a good idea do you have any other ideas of how to stop the external alarm if it doesn't stop on its own? I am terrified of having a really loud alarm that I can't stop. My neighbours would be furious

 

[Neil a]

No don’t cut any wires like said take out mains fuse and battery from internal panel but if the bell box has an internal battery it should sound for 20mins then cut off /go flat
When you pull fuse panel may sound to tell you power fail and also when you open panel it will cause a tamper which will sound internal sounders
But once all power removed is will silence them (apart from bell if got battery)

 

[New Tes]

OK thank you. Will try this tomorrow morning. Wish me luck.