Also check for 0v on the cable you remove from the strobe terminal at the panel, you may have a short on the strobe trigger cable.

Good observation

Thanks a lot for the helpful advice - this forum really is great.

Can you confirm that removing the -ve Strobe from the panel won't affect the BellBox in any other way? (I'm worried that the bright flashing might become annoying to the neighbours so could I leave just leave it off for a few days if I wanted/needed to get an engineer out?)

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Chris.

Thanks a lot for the helpful advice - this forum really is great.

Can you confirm that removing the -ve Strobe from the panel won't affect the BellBox in any other way? (I'm worried that the bright flashing might become annoying to the neighbours so could I leave just leave it off for a few days if I wanted/needed to get an engineer out?)

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Chris.

It won't have any adverse effect, just won't fire the strobe unless there is a short in which case the strobe will still flash even with the core disconnected and you will have possibly found the problem!

Brilliant - I'll update tomorrow.

With the Strobe cable to the BellBox removed:

Potential between 0V and 12V is actually 13.65V

The STR is at 1.25V wrt 0V (and -12.4V wrt '12V')

The Strobe Cable from the BellBox is at 5V (wrt to the Panel's 0V)

Does this imply that the Control Panel isn't sending a high enough voltage to the BellBox?

Hope my readings make sense, thanks for the help!

Chris.

Not sure how you're measuring, red lead from multimeter should stay on 12v positive and take readings of terminal and cable with black lead.

terminal - 12.4V

cable - 8.65V

To be honest I was looking for a reading of 0v or close on both, with the cable removed from the terminal does the strobe stop flashing?

If so there is something wrong with the panel or programming.

Yes the strobe has stopped flashing. but according to rjbsec's earlier post that it what should happen? Is that not the case?

Yes the strobe has stopped flashing. but according to rjbsec's earlier post that it what should happen? Is that not the case?

Disconnecting the core from the strobe output has stopped the strobe?

Then that means that the strobe output from the panel is active even in day mode and it shouldn't be - the panel is faulty or there is a programming setting that needs changing.