First checks
- Test the outlet with another device and bypass a questionable extension lead.
- Confirm the adapter is the correct voltage and polarity for the router.
- Reseat the power connector and check for physical damage or heat.
How to interpret the result
If the adapter has an indicator, its behaviour can help isolate the fault. A router that remains completely dark with the correct working adapter may have failed hardware. If lights appear briefly and go out, disconnect all network and USB cables and retest power only.
What this symptom usually does not prove
Do not substitute an adapter merely because the plug fits; incorrect electrical specifications can damage the router or create a safety risk.
Escalate with useful evidence
Record which devices are affected, whether Ethernet and Wi‑Fi behave differently, the router or gateway status, and the exact time of the fault. This evidence helps distinguish a local client issue, radio problem, routing policy, upstream service fault or failing hardware.
Before a factory reset
Restart the relevant device first and save any ISP, Wi‑Fi, reservation, port-forwarding or mesh information needed to rebuild the network. A factory reset is a configuration-recovery action, not a universal diagnostic test.