Technical Wanted: Croma Alarm siren

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Technical Wanted: Croma Alarm siren

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Hi,
Following strong winds the other night, when my alarm was triggered repeatedly, I've been have alarm troubles with my Croma. Same symptoms as others have reported, "alarm not available" message and alarm going off while driving. Studying the symptoms carefully, I'm pretty sure this is due to an old, undercharged battery in the siren unit.
I was wondering if anyone has an old Croma siren they would like to sell me so I can investigate before I take mine off (It's started behaving again)? I'm happy to buy, or if you took yours off to stop the problem and still have a Croma, If I can confirm the problem and find a solution, I can return a fixed one to you.

Robert G8RPI.
 
Hi Robert Just spent ten minutes to have a look I disconnected ours some time ago, any way the battery is easy to get out just two clips on the siren, the battery part no is 30AAAM6BL and is a single row of AAA nimh Battery’s the connector looks pretty standard. Our alarm drove us nuts going off at all hours with no cause do you think this battery is responsible?.
 
Hi,
It's my best guess based on how mine is behaving. But apart from that something on mine is setting the alarm off in high winds, even with the tilt and ultrasonic detectors turned off. May be a badly adjusted bonnet switch or glovebox light, but I was'nt in the mood to investigate at 3AM with the alarm going off. After that I had various "alarm not available" and going off when driving until I'd done a longer trip. Assumption is this charged the siren battery enought to get it back to normal.

Robert G8RPI.
 
Re: Croma Alarm siren issues

Sorry for the delay in updating this thread, but I wanted to make sure it had settled. So I took the siren off my car, easy job, and opened it up. At first glance the battery (7.2V 300mAh 2/3AAA cells) looked OK as was the voltage. However closer examination revealed the the battery connector was corroded and there was some corrosion on the printed circuit board (PCB). It's classic nicad/nimh "black wire" corrosion. The leaked electrolyte had run down the strands of the wire to the connector. So I removed the connector completly, cleaned the PCB and conformally coated it for ongoing protection. Soldered the battery connections to the PCB Refitted it and it's been fine through two storms since.
For those who don't want to mess with the PCB but want to loose the "alarm not available" warning I'd suggest opening the alarm, removing the battery completely and diconnecting one of the black wires from the PCB to the sounder part of the siren Insulate the disconnected wire with tape. put it back together and refit and connect to car. The alarm won't make a noiise as the sounder is disconnected, but as long as the PCB isn't damaged it will still report to the body computer and the warning should disapear.

Robert G8RPI.
 
Hi Robert, Good to know that you got it sorted. Mine's not worked for a couple of years and I'd imagine it's a similar problem.

When you get a moment I'd be grateful if you could confirm that this is the unit inside the drivers side wheel arch behind the lining cover please?
 
Hi Robert, Good to know that you got it sorted. Mine's not worked for a couple of years and I'd imagine it's a similar problem.

When you get a moment I'd be grateful if you could confirm that this is the unit inside the drivers side wheel arch behind the lining cover please?

Yes, that's the unit. Loks like this
siren.jpg

Note the bracket is slotted so you don't have to remove the nuts completely to get it out. There is a tab behind the mounting bolt on each side. If you prize them up the two half's of the case come apart.

Robert G8RPI.
 
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