False Alarm From Wired Pir

[cybergibbons]

I'm not an installer, but I did used to get asked to fix alarms. I'm never going to help anyone with an old alarm ever again though. You replace the battery. Then a door contact stops working. Then a PIR. Because you touched it first, it's your fault. 

 

It's so rarely worth fixing anything older than 15 years IMO. I remember the first PIR I harvested from a skip in about 1995, probably a high end unit, and it's total **** compared to the ones that come with a Yale wireless alarm.

[Oxo]

Ahh midnight Tuesday post.

 

Pub night!

[james.wilson]

Ahh midnight Tuesday post.

 

Pub night!

sorry then

[Oxo]

Accepted.

[james.wilson]

lol

[Oxo]

Knobler

[petrolhead]

All the electrolytic caps in the various parts of the sytem will be dried out a lot by now leading to instability and less immunity to externl influences. You have had your money's worth out it, and if the wiring tests good changing the panel and detectors and bellbox won't cost much at all and will look nicer, work better and have more convenience features. Faffing around to save £200 or so isn't worth it when your neighbours are pissed off at the constant false alarms and you end up contributing to the lack of attention anyone pays to a sounding alarm.

[Scotmod]

Thanks for the more useful replies. I will check the battery again for DC and any AC on top; measure the wiring etc. maybe replace everything with the suggested Optima unit (very good value if it is good quality?). But I would like to see if there is a simple explanation for the false alarms first.

 

I'm still not 100% sure of the best way to measure the wiring resistance. Do I need to jumper the tamper circuit in the panel, then measure the PIR wiring with the wiring disconnected from the panel but with the PIR still connected? ...or do I remove mains, remove battery at the panel first?

 

(Yes I could get a company in but this is a DIY forum and I like to DIY; I have all the manuals, diagrams, and service procedure for the panel ).

 

The simple explanation of the kit is it's deteriorated due to it's age. I'd also hazard a guess that the battery in your bell box is duff too (if you have one) so any would be burglar could just rip it clean off the wall and no one would be any the wiser.

 

The Optima is a decent, cheap panel. Will do everything you'll ask of it and from a DIYer point of view there isn't really much you can do wrong to it. Most people on here don't fit them or they have their own preferred budget panel but the Optima in a solid design currently in its fourth iteration. 

[james.wilson]

I like the optima / accenta feature wise it does very well and is stable now. I know some say the early G1's etc wernt but the g4's are a great panel imo for the money and features

[bee_man]

I'm not an alarm person, my background is in electronics. I agree fully with the comments made here about life of relays and especially the electrolytic capacitors. Normal life of the capacitors is 1000 or 2000 hours at 85C, increasing considerably as the running temperature decreases. But it isn't the 200000 hours that yours have suffered. There's a very good chance that when you open the lid the caps will have bulging tops,  or have popped and spread corrosive gunk and conductive foil everywhere. This is the reason that electrolytic caps now have a deep marked cross on the top, so that when they fail it is in a predictable manner. I bought a 4 year old panel to play with and learn on, and routinely changed all the electrolytics. The main smoothing cap was bulging and not too far off going pop. It's often exacerbated by poor design, putting the things next to hot heatsinks and drastically reducing their life. You are even getting close to the 30 years life expectancy of semiconductors!. Bottom line - do what the guys here are telling you, replace it.

 

bee