When I do an 'Alarm Test'

1. the bell sounds fine

2. the strobe flashes fine

3. the sounder sounds fine

When I set the alarm, then trigger it to test only the bell comes on and not the strobe.

Anyone any ideas? I have spent all day trying to figure this out and it is doing me in.

If you know what bellbox it is that would help more but some strobes are very hard to see during the daylight. Try when it is getting darker and if that fails either it is a wiring problem or a faulty bell.

Do you know how many cores go to the bell side in the panel? Remember there is 240v present in the panel itself.

If you are not sure then i would advise you to call an engineer.

Thanks for your reply, it is a Ventcroft Classic nt Bell / Strobe combination.

Like I say, when I do an 'Alarm Test' I can trigger the outputs individualy from the panels key pad (from the second option menu)

This confirms that the strobe working as I can see it flashing.

One point to note is that when I do the test I have to trigger one of the sounders first. I can then switch the strobe on and off. Then I can switch the sounder off and still switch the strobe on and off.

I am now thinking it could be a software fault with the panel which is running version 1.0 software.

Any more ideas? Is the strobe on a delay perhaps?

The bell has 6 core going to it and only 5 of the cores are used.

By the way I am an electronics engineer and this has got me stumped.

Sounds like a programming issue to me. Not familiar with the panel, but check it isn't set up to flash the strobe on a confirmed alarm only.

I know on the older Accentas to operate the strobe you had to first operate the internal sounder ie test option 2 then 4, and 0 to switch off, but as to have the strobe only test once a sounder had been switched on then off does sound like a system fault.

I would try defaulting the panel and then reprogramming?

Good luck

Thanks for your suggestions guys. I'm pleased to say that a month on I have fixed it.

The outputs from the panel were measuring ok when loaded, so I figured it must be the strobe circuit in the bell box.

I deduced that I could get the strobe to operate consistently only if I applied a positive to STB - before I applied 0V to trigger it. I guess that triggering the internal siren first must have held STB - slightly higher on the panel than normal hence why it would work as described above.

A brand new Ventcroft later and the strobe is working as expected. I even wired the two up just to prove that the strobe would work on the new one while at the same time not on the old one.

Circuitsight.