I installed an Excel system five years ago and all has been working fine until about a year ago when I started getting intermittent faults.

At random points I got (in sequence):

- Bell/System Tamper Alarm

- ALARM Activated

- Bell/System Tamper Restore

...all in the space of less than a second (according to the log via the UDL software) and these events occur whether the alarm is set or not and without anyone touching the system. And whenever the alarm is set the sounder goes off.

In 2010 I installed a new Yuasa NP7-12 12v 7Ah battery to replace the original Texecom branded item (installed in 2006) and that appeared to cure the fault.

Almost exactly a year to the day the fault came back!! and I do not think the battery is faulty this time (tried charging, it placing a load on it and monitoring the voltage drop).

I've been trying to find the problem but no joy - checked for loose connections, voltages, etc. In the process of running the checks I noticed that the strobe on the bell box has stopped working, though I'm not sure if that is a related problem or not.

Help! Any constructive suggestions as to what the cause may be or how I can track down the cause please?

Help! Any constructive suggestions

check the voltage , current & resistance readings & check agaist those teken on install

Very diplomatic Mr H, not like you at all

Very diplomatic Mr H, not like you at all

Yeah I worru my a/c's been hacked....

OP's on other channel too, I posted the same thing a little over a year ago.

This time I reckon battery fuse (as a long shot) & by asking for volts amps & ohmmns the fuse will be checked twice w/o looking

damp bellbox

Mr Happy - your patience with a DIY'er is appreciated (even if it is one year hence and on a different forum!)

The current results from the Luxembourg jury are as follows (I'm afraid that I didn't take readings at install; that's what you get from someone who 'thinks' they can install an alarm!) From left to right on the panel:

AC - 19.17v

Batt - 13.91v (battery gives 12.83v when not connected to the panel)

SAB

(Odyssey 3)

Strb - Initially was fluctuating between 13.05v and 13.10v but when I rechecked everything it read as a steady 13.06v

0v - 0v

Tamp - Initially fluctuating 0.85v - 0.90v then 0.74v steady

Bell - Initially 12.50v - 12.55v then 12.51v steady

+12v - 13.94v steady

AUX 12v Connections

+ - 13.91v

- - 0v

SW+ - 0.65v

Auxilliary Tamper Connections

Tamp (Left) - 0.86v

Tamp (Right) - 0.86v

Keypad

T - Fluctuates between 11.34v and 11.94v

R - Fluctuates between 11.34v and 11.94v

(0v difference between T and R)

- - 0v

+ - 13.91v

Zones 1-8 (1-5 & 8 PIRs, 6 door contact, 7 just has an EOL resistor installed at the panel, i.e. not used)

Left - 13.75

Right - 9.35

Resistance

Aux Tamper - 0.003ohm

All fuses are working, including the battery fuse.

And that concludes the voting from the Luxembourg jury - Pays de Galles null point!

Any other measurements?

Update: SAB voltage fluctuations were caused by SAB being in 'Hold Off', once this is removed then voltages remain stable.

Been up and HAD A LOOK INSIDE the SA or EWB as it's supposed to be called now?

Mr Happy - your patience with a DIY'er is appreciated (even if it is one year hence and on a different forum!)

Any other measurements?

only one that you need was the one not taken - what V between 12v and SAB tamper.

save time, it`ll be the switch on the bellbox thats faulty.

Any other measurements?

current,