Scantronic 9751 rewiring, house refurb

21 Jan 2023
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United Kingdom
Hi all,

Hope I could pick your technical brains, I am a carpenter by trade however I have some limited and extended knowledge in other areas of construction work - alarm panels is one of those limited skills, by limited I mean no skills!

I have a basic understanding of how alarm panels work however its theory so you will need to be specific with your replies please.

In simple there are 2x cables (external sounder and room motion sensor) which are running visibly on the skirting board in the backroom. This alarm was installed well before I bought the house. Now that I am refurbing that particular room I want to hide those cables into a new partion wall.

Previously I reset the main engineer code so have seen the inside of the panel, at that time the decorator removed a sensor from the office/study (without me knowing) and then shorted the cables as he is removed cables from the sensor housing as he wanted to fill and paint behind the sensor. I believe from memory the AUX fuse had burn't out so that was replaced after the sensor was wired back up and the system reset and worked fine. After that I also installed a new battery some months later.

I made an assumption (don't shoot me down) that removing the AUX fuse this time around will allow me to remove the wiring from the sensor in the backroom so I can reroute it but once I remove the fuse the external sounder goes off, putting the fuse back in stops it. The cables will have to be removed from the panel and then rerouted and brought back, I can not access the wiring from the backroom sensor or external sounder due to access issues.

No way am I assuming anymore and would like professional guidance, I believe its a quick fix and the local alarm engineer can only come out next week for non-emergency appointments, hence my question to you all.

Sorry for the insight above hopefully it helps somewhat, but in simple:

1) Which cable is for the external sounder? - For the motion sensor I will just follow the room sensor cable and figure out where it connects in the panel
2) How can I remove both of these cables without the external sounder going off?
3) It is just a case of reconnecting once rerouted and then perform a reset?
4)If for whatever reason the rerouting takes longer than expected, can I just leave the panel installer mode for a few days or if I am going out can I reset the alarm so everything else works besides the backroom sensor and the external sounder - I do have a internal sounder.

I would be grateful for step by step instructions as I can not wait for the alarm guy and as mentioned I have reset the engineer code in the past, so once popping in the code and entering installer mode and removing the panel, I am lost!

Many thanks in advance, really appreciate your input, see the pic below of my panel



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Ignore the bell.
Remove the zone cabling to the pirs you wish to re-route
Remove the 12v 0v feed for them
Re-route and put back as they were
Exit engineers mode

Ignore the bell.
Remove the zone cabling to the pirs you wish to re-route
Remove the 12v 0v feed for them
Re-route and put back as they were
Exit engineers mode

View attachment 293228
Hi Tiger, thanks for that. Just to clarify to remove the sensor, just simply remove the red, yellow, white and green cable for each sensor i want to reroute?

Unfortunately I can ignore the bell (external sounder) as i need to reroute that cable too as mentioned above.

Would be grateful if you have the solution for the removal of the bell wiring to reroute it without the bell going off outside

Thank you.
Bell will only sound for 15-20mins if the battery inside it is still healthy once the power to it is removed
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Thanks Tiger, shall i just remove the 5 connections you labelled at the top?yellow,green, black, red and yellow. Guessing all of these 5 strands are within the core of the bell cable?

Was hoping there was a way to not sound the external sounder at all. I live with many elderly people on my street and i know they will all come running out!

Surprisingly when the decorator blew the AUX fuse in the past the outside bell did not sound or the internal sounder and it was in installer mode then.

Thanks in advance.
I’d guess your top 3 cores then the lone 12v + and -. Best bet would be to trace the O/P cores I labelled as bell that will lead you to the others for certain.
Thanks much appreciated, i will give it a go when i next get a chance.
Hello tiger, I had some work done recently In kitchen I wanted to know how I can disconnect one of the sensors, do I just remove the corresponding wires from the zones. To be exact looking to remove zone 2 as no longer needed. If I done will zone 1/3/4 still work?
Remove zone wiring and power to the sensor from aux 12v and 0v.
Enter installer mode and disable zone in programming.
Thanks for this are you able to advise how I disable the zone in the programming?
Engineer code > zone number ( I.e 02) > yes/enter > 00 Not used > enter > back to installer mode > 99 enter escape installer mode
Hi Tiger, hope you are well. Thanks for your help, surprisingly I did not get a chance to try your method out as the room as I am decorating has become a huge project.

Cut a long story short, I need to extend the wires and its pretty much impossible to pull the old cables out as they have been pinned done with grips under the floors and in the stud wall. Could I simply cut the external bell wire and room sensor wire and then just add a longer cable in the middle for each wire.

Also would I just rewire these into electrical terminal blocks or those gel line BT telephone terminal blocks?

Please can you explain what I should do step by step, if I can simply cut the wire - I am worried I may short some fuse somewhere.

I can put the system in engineers mode and can cut the power from the fuse, I am worried if I remove the battery and cut the cables I may need to reprogram and I have no idea what to do then.

Thanks again in advance, sorry to raise another question after you have already helped.
Take aux volts connection out of control panel and extend cable with these junction boxes.
Reconnect in programming required.


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Take aux volts connection out of control panel and extend cable with these junction boxes.
Reconnect in programming required.
Thanks Handymanjo for your reply, just a quick one, where am I removing the AUX volts connection on the panel? If I am honest, I don't fancy unwinding all the greens and whites (if these are AUX for each cable) as the space is tight and no real slack on the cables. Unless the AUX are other cables which can easily be removed.

Hope that makes sense, such a pigs ears of an install, no slack anywhere, even the cables just reach inside the motion sensor.

Also I know Tiger answered but if you have any experience with this unit, can I completely silence the unit so when I make any disconnections no bells ring internally or externally., thanks in advance.

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