Why? Those cores go direct from keypad to the panel not via sensors? Or do you suspect another damaged cable or is it curiosity??
Thanks, Sharpend,
Guess it's out of curiosity combined with lack of knowledge of what was actually inside the keypad. Had I look and now know (thanks for the input nonetheless).
Have done various checks, tests, replacements and re-wires. To recap:
1. Changed affected PIR sensor (assuming that was the fault). Didn't fix the problem.
2. Did a walk through test (see above)
3. Tested battery away from panel (see above)
4. Tested battery under load (see above)
5. Replaced battery in any case
6. Disconnected each of the sensors from the main panel / linked out affected zones (3 and 4) one by one. In each case the panel then behaved normally (i.e. no solid red light for that sensor on the panel when I went to set it).
7. Connected a short piece of alarm cable to the corresponding sectors on the panel with one of the 'affected' PIR sensors attached, then set the alarm. All normal on the alarm and PIR (i.e. no solid red light on the panel for that sector as above and the sensor on the short cable worked normally / set the alarm off when I walked in front of it (which it hadn't been doing in its original position in the house)).
8. Did the same for the other affected zone on the panel. Same normal result as above.
9. Reconnected the original PIR wiring for the affected sensors, went to set the alarm, and the same problem (solid red light for each zone).
10. Tested each of the zones at the panel (multimeter set to test continuity (200 Ohms)); a) with PIR not set off, b) with PIR set off (walked in front of).
Bold are the problematic ones. Power on (12v).
Results
Zone. reading not set off / reading set off (tested the 'good' PIRs just to make sure working normally showed up as working normally on the multi-meter):
1. 28.7 / 1.
2. 28.9 / 1.
3. 1. / 1.
4. 1. / 1.
5. 30.8 / 1.
Then twisted green / yellow wires at PIR end and tested:
3. 1.
4. 1.
Conclusion: break in alarm wires to affected sensors.
11. Twisted each of the alarm wires (green/yellow) in turn together with the
black earth (I know the black earth is working as there is power to the sensor) at the PIR end and tested for continuity at the panel in each case. Got continuity with the green/black twisted together (not with the yellow). Conclusion - green wire intact / yellow broken (cause of problem?). Disconnected the yellow from the PIR then, using one of the cores from some spare alarm cable, bridged across from the yellow connection to the earth connection in the PIR. Then bridged across from the earth to the yellow side of the circuit for the zone for that PIR at the panel. Tested for continuity at the zone in the panel and now showed continuity (hadn't before). Conclusion - now have alarm circuit via the green wire and earth cable (tip from elsewhere).
Set the alarm. (Now re-wired) PIR still showing solid red at the alarm keypad! (but again, the actual PIR red light goes on and off as normal when you walk in front of it).
12. Looked inside keypad (the keypad seems to make a funny chirping noise alongside it's usual beep beep beep.)– wiring all ok
Now stumped.
