Start by reading the router's status LEDs. A dark power LED points to PSU or outlet failure; a solid power light with a red or off WAN light points to an ISP or modem fault; blinking activity with no internet usually means a WAN authentication or DHCP problem. Address each layer in that order.
Symptoms
- No LEDs at all, or only the power LED lit with no WAN or LAN activity
- Wi-Fi SSID visible but clients get 'no internet' or a 169.254.x.x address
- Connection drops every few minutes, often under load or on 5 GHz
- Admin panel unreachable at 192.168.0.1 or 192.168.1.1
- Router runs hot to the touch and reboots itself unpredictably
Common Causes
Failed power adapter or wall outlet
Cheap 12V adapters degrade after a few years. Output voltage sags under load even though the LED still lights, causing random reboots or a dead unit.
WAN link or ISP session failure
The modem lost sync, the PPPoE credentials expired, or the ISP is provisioning a new IP. The router itself is healthy but has no upstream path.
Corrupt or outdated firmware
A partial update, a bad NVRAM write, or an aging firmware branch causes memory leaks, DHCP hangs, and Wi-Fi radios that stop responding after hours of uptime.
Thermal throttling
Blocked vents, dust in the heatsink, or a router placed on carpet push the SoC past its thermal limit. Symptoms include slowdowns, dropped clients, and spontaneous restarts.
Configuration drift
Manual changes to MTU, channel width, DHCP scope, or firewall rules can silently break connectivity, especially after an ISP swap or a new device joins the network.
Step-by-Step Fix
- Read the LED pattern before changing anything
Match the front-panel LEDs against the label on the underside of the router. Note which lights are off, solid, or blinking. This tells you whether the fault is power, WAN, LAN, or Wi-Fi, and keeps you from resetting a router that only needs a modem reboot. - Verify power delivery with a known-good adapter
Unplug the router, wait ten seconds, and plug directly into a wall socket, not a switched strip. If you have a spare adapter with matching voltage and polarity (check the barrel symbol), swap it in. A router that only wakes on the second adapter has a failing PSU. - Power-cycle the modem, then the router, in order
Shut down both devices. Unplug the modem for at least 60 seconds so the ISP session ages out, then power it up and wait until the online LED is solid. Only then power the router. Booting them together often leaves the router with no WAN lease. - Test the WAN link from a wired client
Plug a laptop straight into a LAN port and check whether you get a private IP from the router (ipconfig on Windows, ip a on Linux). If the LAN works but there is still no internet, the fault is between the router's WAN port and the ISP, not inside your network. - Log into the admin panel and check WAN status
Open the gateway address shown by ipconfig, sign in, and open the WAN or Internet status page. Look for the assigned public IP, gateway, and DNS. An empty WAN IP or a 0.0.0.0 gateway confirms an ISP-side issue or wrong PPPoE credentials. - Update firmware from the vendor's site
In the admin panel, note the current firmware version and hardware revision, then download the matching build directly from the manufacturer. Apply it over a wired connection, never Wi-Fi, and do not power off during the flash. Reboot and retest. - Clear thermal and interference issues
Move the router off carpet and away from AV cabinets, power bricks, and microwave ovens. Blow dust from the vents. On 5 GHz, drop channel width from 160 MHz to 80 MHz if clients disconnect under load; DFS radar events force silent channel changes. - Factory reset as the last step
Hold the recessed reset button for about 30 seconds until the LEDs cycle. The router returns to defaults, so you will need to re-enter your ISP credentials, SSID, and Wi-Fi password. Only do this after firmware and hardware checks, and export a config backup first if possible.
Common router symptoms mapped to the most likely cause and first action
| Symptom | Likely cause | First action |
|---|---|---|
| All LEDs off | Failed PSU or dead outlet | Swap adapter, try another socket |
| Power LED only, no WAN | Modem or ISP fault | Power-cycle modem for 60 seconds |
| WAN LED solid, no internet | DNS or PPPoE session | Check WAN status in admin panel |
| Wi-Fi drops every few minutes | Channel interference or heat | Change channel, improve airflow |
| Admin page unreachable | Wrong gateway IP or firmware hang | Run ipconfig, then reboot router |
| Router reboots on its own | Overheating or dying capacitors | Clean vents, plan replacement |
Prevention
- Replace consumer-grade routers every 4 to 6 years; capacitors and radios degrade
- Enable automatic firmware updates, or check the vendor's release notes quarterly
- Keep the router vertical, elevated, and away from heat sources
- Save a config backup after every working change so recovery is a single upload
FAQ
How do I know if the problem is the router or my ISP?
Plug a laptop directly into the modem, bypassing the router. If the laptop gets internet, the router is at fault. If it still fails, the modem or ISP is the issue. You can also tether a phone on mobile data and compare; a working tether while home internet is down points upstream.
Will a factory reset erase my Wi-Fi settings?
Yes. A hard reset wipes the SSID, Wi-Fi password, admin password, port forwards, DHCP reservations, and any PPPoE credentials. Every device will need to reconnect. Export a configuration backup from the admin panel before resetting whenever the router still responds, so you can restore settings after the reset completes.
When is it time to replace the router instead of repairing it?
Replace it when the hardware is past vendor firmware support, when it reboots under normal load even after a factory reset, or when it cannot deliver the throughput your ISP plan provides. Routers older than roughly five years often lack modern security patches and Wi-Fi 6 features, which limits both performance and safety.
Book a network diagnostic session with our IT support team to identify the root cause and restore stable connectivity.