On Friday, November 22, 2013 11:12:21 AM UTC-5, Tony Hwang wrote:
wrote:

On Friday, November 22, 2013 1:35:28 AM UTC-5, Danny D'Amico wrote:

Dead alarm system troubleshooting advice requested ...



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Yesterday, I had been messing with the main breakers, and accidentally



shut the main 200A breaker without turning off the power generator switch;



so the Generac kicked in; and I heard the alarm system in the garage



vehemently complaining with persistent loud beeps.







I immediately reset everything, and I thought it was all ok.







Then, today, the alarm system sounded three loud long beeps, and



went totally dead.



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Troubleshooting with my Fluke after removing the alarm system external



wires shows the external ELK-TRG21640 16.5VAC, 45VA power-supply



transformer plugged into an outlet has an open secondary, and when



plugged into an extension cord, there is no voltage from any of the



three screws on the secondary windings:



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If I thought it was that simple, I'd just replace the transformer;



but I wondered why the backup battery didn't run the alarm system.



Testing the 12V 5AH battery out of the alarm system shows it's 13.5



volts DC (no load open circuit voltage), which, at least seems OK



(I don't know how to load it though):



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So, two things must be wrong:



1. The ELK AC transformer secondary opened up suddenly



2. Maybe the power supply inside the alarm system box went bad suddenly



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Do you think shutting the breaker without turning off the generator



could have blown the alarm system?







It shouldn't, but you'll never know if your experimentation

somehow caused it or if it was just a coincidence. There is no

question that home generators of various types have been known to

screw up some electronic equipment at times.







Any other troubleshooting suggestions?





I assume you checked for any low voltage fuses?



Hi,

Just start with replacing the x-former and battery. I strongly suspect

battery is no good.

It's easy enough to verify that the battery is or isn't the problem.
He's got 13.5V on the battery with no load. That doesnt' sound like
a bad battery to me. All he has to do is measure the voltage with it
connected to the alarm. If it's 12V and the alarm isn't powering up,
then it's not the battery.


When you check the voltage did you remove a lead

from battery terminal since you mentioned no load voltage.

Your battery is not holding charge so when x-former quit, it couldn't

supply the necessary juice.

Good grief. It's charged to 13.5 volts