Texecom Intermittent Bell Tamper

[Guest RicN]

Got a Texecom R8 and two Aztech bells installed by previous owner, less than 12 months old. Started getting tamper faults and front bell going off (leds on bell confirm tamper too) so opened control box and noticed strobe- wire to the front bell almost cut (suspect previous owner did self install, cannot find any company with same name as on bell box, and no phone or other contact details supplied), which after powering down completely I fixed.

All was well for a week, then get another bell tamper (this time confirmed in the log as I managed to get a system reset and now have engineer access) and front bell also shows tamper on it's leds. Rear bell doesn't make a peep. Resetting stops bell, but tamper fault stays. Panel is also set to only have internals on unset tamper too, so I suspect bell is doing it's own thing.

This evening the front bell starts going of for repeated short busts, 2-4 seconds, with about as much time again between them.

Fitting a link across the tamp and 0v on the SAB terminal block on the control board, which is what I presume is meant by "replace system tamper link" in the troubleshooting section, makes the bells stop and kills the tamp warning on the RKP, and removing instantly sets off front bell again. Noticed that I was getting 8.4v on the TAMP terminal on the board and also at the join between the two bells, before I put the link in. All connections seem firm, shiny and otherwise OK.

Am I right in suspecting a problem with the bell boxes? I would have thought both would have gone off if the tamper circuit was broken. I've no idea how they were set up as doing a spiderman impression out of a window to inspect them is not my idea of fun. Weather conditions have been varied if this could be affecting the tamper switches within the bells.

Thanks for any ideas - even if it's getting in a professional to take a look.

[dpaengineer]

Sounds to me like a faulty tamper switch on the bell. Time for a replacement me thinks.

[Guest RicN]

Replace a bell that's barely 12 months old? What do they do, fit service timers to them?

If anyone can recommend a service engineer in the south birmingham area that would be much appreciated, especially if they give discount to people on this board

[arfur mo]

hi, you say you have 8.4v at the tamper return, what voltage is read from the negative hold off terminal? i.e. the supply to the bell. i would hope for no more than 1.5 voltage drop between the two measurements.

if this, as i suspect is too close to the lower limits of the sirens or panel it can be misleading to diagnose.

example - if the threashold for siren 1 is 8 volts, a short mains interuption, even with a good battery the rail voltage will drop from 13.6 to 12.0 8.4 becomes perhaps 7.8 volts and can cause a 'ghost' tamper. the additional current drawn by the siren sounding due to the supply rail voltage drop will cause a siren to sound in 'SAB' mode, this causes a further voltage drop to the tamper return terminal and cascads into a tamper alarm.

not knowing the texacom panels that well, but suspecting you are too close to the lower voltage threshold. the siren circuitry nearly always drops the return voltage measured at the 'tamp' terminal by a 1 or 2 volts. if you have 2 sirens wired in series

PANEL SIREN 1 SIREN 2

HOLD OFF -VE------------ -SUPPLY

TAMP RET-------------------- -SUPPLY

TAMP---------------------------------------------------------TAMP RET

then you are dropping the return voltage still further and only feeding the 2nd siren with 8.4volts, and can cause the 2nd siren to 'blip' intermittently, although the panel may or may not actually go into tamper.

suggestions

if both sirens are wired directly back to the control unit, temporary bypass the rear siren by simply taking the -ve to that siren to the -12ve detector supply and not connecting the 'tamp' return wire to see if the system and sirens behave.

or if the panel has a 'universal' or 'aux' tamper circuit in the panel, you could use this for the rear bell -ve supply and tamper return. its a more elligant option which will at least tell you which siren has a problem if any from the log, but make sure the siren is fed first in line of the neg supply of this tamper loop if other tampers are wired in, otherwise openning say a pir will cause the external siren to sound even in engineer mode.

you can see from above it may be a simple fault to cure and my suggestions will i feel sure clear the problem up. i recommend you need an experienced capable service engineer to have a good look at all your system, this need not be a big company as there are many small and good companies arround - like mine but i do not take on work in Birmingham being based in Essex.

none of us like paying out dosh but think of it this way, you got the alarm effectivly 'free' with the house, you could have paid anything upwards of