Nexus 8 - Bell Fault - Any Ideas

[DaiEdwards]

I have a Nexus 8 Alarm with a Vortex bell box. The system has worked perfectly since I installed it in late 2003. However, I recently became aware that although the system behaves perfectly with panel speaker sounding and strobe flashing when alarm is triggered the bell is not sounding. A bell test will also not trigger the bell. However, I can trigger the bell by removing the bell fuse and then replacing it. The fuse is fine.

Maplins kindly "lent me" a replacement bell box and when connected up it behaved exactly the same as the original - i.e. LEDs showing operational state, strobe working as required but no bell trigger. I did this test through a new wiring loom. This leads me to the belief that the panel is somehow at fault. I have reset to factory defaults and then reprogrammed entire set up. All with no success.

I also called the lynteck tech line at

[camerabloke]

takr the bell trigger out and connect it to a negative and see if the sounder goes off, iff it does its a prob with the output

[DaiEdwards]

takr the bell trigger out and connect it to a negative and see if the sounder goes off, iff it does its a prob with the output

Thanks for the rapid reply - I presume that you mean prob with the panel output?

I will try tomorrow (neighbours would not thank me for trying now!)

[camerabloke]

Thanks for the rapid reply - I presume that you mean prob with the panel output?

I will try tomorrow (neighbours would not thank me for trying now!)

yep, if the bell rings when you do the above, then the output is programmed wrong or it is blown

[DaiEdwards]

yep, if the bell rings when you do the above, then the output is programmed wrong or it is blown

No joy getting the bell to ring (story of my life!). I now wonder whether my bell test on the borrowed bell box was flawed because the panel box was open?

Anyway, with panel box "closed" (tamper switch taped back in place) the voltages across the bell/strobe terminals are as follows:

Alarm unset and armed:

Tamper to Hold- 0

Tamper to Hold+ -13.2

Tamper to Trg -13.2

Tamper to Str -12.1

Hold- to Hold+ -13.2

Hold- to Trg -13.2

Hold- to Str -12.1

Hold+ to Trg 0

Hold+ to Str 0.1

Trg to Str 0.2

Alarm triggered and panel speaker sounding:

Tamper to Hold- 0

Tamper to Hold+ -13.2

Tamper to Trg -0.6

Tamper to Str -0.6

Hold- to Hold+ -13.2

Hold- to Trg -0.6

Hold- to Str -0.6

Hold+ to Trg 12.5

Hold+ to Str 12.5

Trg to Str -0.05

Does this look as though it should be triggering the bell and perhaps it is the bell trigger mechanism that is faulty not the panel?

[camerabloke]

looks like bell is shot

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[DaiEdwards]

looks like bell is shot

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I wonder if Maplins will be kind enough to lend me one a 2nd time! I do not fancy spending

[camerabloke]

Hope you get it resolved Dai

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[lawandorder]

No joy getting the bell to ring (story of my life!). I now wonder whether my bell test on the borrowed bell box was flawed because the panel box was open?

Anyway, with panel box "closed" (tamper switch taped back in place) the voltages across the bell/strobe terminals are as follows:

Alarm unset and armed:

Tamper to Hold- 0

Tamper to Hold+ -13.2

Tamper to Trg -13.2

Tamper to Str -12.1

Hold- to Hold+ -13.2

Hold- to Trg -13.2

Hold- to Str -12.1

Hold+ to Trg 0

Hold+ to Str 0.1

Trg to Str 0.2

Alarm triggered and panel speaker sounding:

Tamper to Hold- 0

Tamper to Hold+ -13.2

Tamper to Trg -0.6

Tamper to Str -0.6

Hold- to Hold+ -13.2

Hold- to Trg -0.6

Hold- to Str -0.6

Hold+ to Trg 12.5

Hold+ to Str 12.5

Trg to Str -0.05

Does this look as though it should be triggering the bell and perhaps it is the bell trigger mechanism that is faulty not the panel?

The above test results are very helpful, the significant one is Hold+ to Trg which should be ov when the panel is unset and roughly 12 volts when the alarm is triggered.

Your test proves that the panel is working properly.

It's not clear whether you did these measurements at the panel or at the sounder but if you did the test at the panel repeat it at the sounder, if you get the same results it suggests the sounder is either faulty or there is a link which you haven't set properly on the sounder.

If the test differs from the one you did at the panel. (you don't get 12v between Hold+ and Trg) it suggests that there is a fault on the Trg core of the cable which runs between the panel and the sounder.

Might be worth wiring the sounder up temporarily on a short peice of cable close to the panel until you get it working.

[zimmerphrame]

...have you checked cable resistances/continuity? try using a jumplead from panel to bell, does'nt need to be a long lead, you can take the bell down and test it next to panel.... I'm used to working on castle panels normally, but 13.2v across the hold off seems a little low to me....(about 13.6-13.8v on castle normally)...