This is an electronic question, it is related to a security panel and the End Of Line Resistor. For those that do not know the EOLR is a resistor that in placed within the protected loop to provide a small amount of current to flow and thus supervises the loop. If the loop is cut it is an alarm, if the loop is shorted it could be an alarm or trouble depending upon the status of the panel. Enough background.
Today I had a strange occurrence with a EOLR. The system was not reporting the zone open even though I was holding the door open and looking at the keypad. After a period of troubleshooting found that the 3.74k resistor was now 5.86k. Replaced with new and all is well. This is the second time in 17 years that this has happened to me. Very Strange??? I wonder what would make it change in this way. Any thought???
Just looking for opinions on this. The environment was a clean office, normal temps, humidity very comfortable. No signs of overheating of the resistor, no corrosion present. All looked as it did when I installed about4 years ago except for the very high value.
Thanks in advance.