Interlogix NS3500-28T-4S User Manual - Manual (Page 360)

360
Solution:
1. AC power cord not inserted or faulty
2. Check whether the AC power cord is inserted correctly
3. Replace the power cord if the cord is inserted correctly, check that the AC power source is working by
connecting a different device in place of the switch.
4. If that device works, refer to the next step.
5. If that device does not work, check the AC power