Scantronic 9448 A/t Fault?

[whitegold]

Good morning, All.

I've searched the forum as best I can, so will have to trouble you with a new post, hopefully this will not stray into "Pro" information.

My diy 9448 Scantronic just threw an A/T fault this morning.

It's been perfectly happy since fitted at least 4 or 5 years ago.

Just checked out the cable resistances (daisy-chained A/T configuration), and there's a total resistance of 15ohms in the Global circuit.

(Several short runs at around 1ohm each, but the two longest are 5 + 7 ohms respectively)

I suspect there may be an element of corrosion in cabling/connections here?

I'm not sure what sort of resistance I should be seeing in this cabling either; it's all 6 core multistrand, but the longest run is out to my garage, must be 40meters at least.

Can't find a figure anywhere for trigger level of A/T circuit on 9448, and as a Yorkshire person I'm psychologically hindered from ringing Cooper's 0900 advice line, which will possibly keep me hanging on for

[FASTCAR]

There are anti tamper switches fitted to the bell , keypad / panel cover also.

Your readings don't seem that high , but investigate any terminations , especially in the garage.

Regards.

[whitegold]

There are anti tamper switches fitted to the bell , keypad / panel cover also.

Your readings don't seem that high , but investigate any terminations , especially in the garage.

Regards.

Thanks for that, Fastcar.

When I first checked the panel it did not shut up until I bridged out the AT associated with the Zone circuits. (However this could be pure coincidence)

I now realise the Bell circuit AT is actually separate, but presumably uses the same panel indicator as the Global circuit (ie the bottom one)

Actually this false actuation @ 0730 would be consistent with the Sun hitting the Bellbox at around this time.

Since this is Yorkshire, I suppose this is not likely to be an issue again until sometime next summer.....

I've thumped the bell box without effect, and I'm reasonably satisfied with the cabling being secure and undisturbed. (On original installation I took time to get it inside cavity walls, under floors and so on)

However, I was looking at replacing the Bell box anyway, before this winter, as the sounder has become pretty numb in its old age, and I fancy something with a bit more snazzy strobe!

I've also soldered and shrinkwrapped all connections on the longest cable run, which has not altered the resistance to any noticeable degree.

Well, thanks again for taking an interest. There's really nothing more frustrating than digging out cabling to discover that there was nothing wrong with it in the first place.

Regards

[breff]

A dud battery can cause a tamper on the 9448, it usually resets straight away though.