I thought I was in big trouble with my system when - this afternoon- I heard two beeps from the panel and discovered no power - on the keypad.
On opening "the box" I was confronted by D1 flashing - nothing else, no LED's on the UCM etc. After a checking AC voltages etc I pulled the off the S12v-com-12v connector and put a meter across the com=12v terminals as going out to sensors etc. I was confronted by 1.9Ω. Next I checked lines to individual sensors and found a PIR that had gone dead short (well 1.9Ω which is likely partly down to cable impedance.)
I have disconnected this sensor for the time being and will put a note of the make and model up here when I replace it.
The main purpose of this post is to ask if there isn't a fusible link or other device on the main board to cover this sort of event.
System has powered up this evening and all would appear to be OK
Last edited on Thursday Oct 22nd, 2020 03:02 am by
There are resettable fuses on the 12V supply to the PIRs and keypads which were activated by the short circuit, and hence prevented any damage to the main controller. If it had been a normal fuse you would have to replace it, but a resettable fuse recovers when the shirt circuit is removed