If your Comcast router won’t turn on, verify outlet power, reseat the cord, try a second adapter, and rule out an outage before swapping gear.
Why A Comcast Router Stays Dark
A dead gateway usually points to lost power, a failed adapter, a tripped surge protector, or a hardware fault. Before you head to the store, run through a tight set of checks. Each step narrows the cause and saves time.
Fast Triage: What To Check First
Start with power at the wall, then the cord, then the device. You want a known-good outlet, a solid plug fit, and a quick sanity check with another small appliance. If lights stay off, move to the adapter and the coax line step.
| Step | What To Do | Expected Result |
|---|---|---|
| 1 | Test the outlet with a lamp or phone charger. | Outlet delivers power; if not, use a different circuit. |
| 2 | Bypass surge strips and smart plugs. | Plug straight into a wall socket. |
| 3 | Reseat the barrel connector on the gateway. | Firm, wobble-free fit; no spark or heat. |
| 4 | Inspect the power cord for kinks or chew marks. | Replace if damaged. |
| 5 | Try a second 12V adapter of equal or higher amp rating. | Lights return, or rule out the adapter. |
| 6 | Check the service status map. | Rule out a neighborhood outage. |
Comcast Router Won’t Turn On: Fast Fixes That Work
Work through these fixes in order. Keep the gateway cool and upright while testing.
Confirm Wall Power And Power Path
Many dead gateways trace back to a tripped power strip or a loose wall plug. Move the adapter to a wall outlet, then press the adapter firmly into the gateway. If your home uses switched outlets, flip the wall switch on. If the outlet is GFCI, press reset.
Use A Known-Good Adapter
Xfinity gateways commonly use 12V DC adapters; the exact amperage varies by model. An adapter that sags under load will leave the unit dark or stuck in a boot loop. Borrow a 12V unit with equal or higher amp rating, match the center-positive barrel, and test for lights. If the gateway wakes, replace the original brick. If you rent the unit, you can swap hardware at an Xfinity store; the gear swap page explains the process and return window.
Look For Life Signs
On recent xFi models, a steady white LED means the unit is on and ready. A total lack of LEDs points back to power delivery. If you see a brief flash then darkness, suspect a failing adapter or thermal shutdown.
Rule Out An Area Outage
Your gateway can be fine while service is down across the block. Use the official Xfinity Status Center to see live outage reports and restoration windows. If the map flags a problem, wait for the fix before chasing hardware.
Reboot The Right Way
Once you get lights, give the unit a clean restart to clear stale states: unplug the adapter, wait sixty seconds, and plug back in. Let it boot fully before testing Wi-Fi. The restart guide lays out the same method for current models.
Safe Adapter Specs And Common Pitfalls
Stick with the correct voltage and a plug that fits snugly. Undervoltage causes resets; overvoltage risks damage. Amperage can be higher than the label; the gateway will draw only what it needs. Heat, smell, or buzzing from the brick is a red flag.
Power Facts That Matter
- Voltage: 12V DC on many models; check the label on the gateway or the brick.
- Polarity: center-positive barrel on stock units.
- Amperage: meet or exceed the printed amp value.
- Line side: US units expect standard 120V AC.
Outage And LED Resources
For live outage info, use the official Status Center and map. For LED meanings on current gateways, see the gateway light guide. Both pages help you separate local power trouble from service events and normal boot states.
When The Router Still Won’t Power Up
If the unit stays dark after a good outlet and a known-good adapter, the gateway likely needs service. Before you swap, record the model name from the bottom label and snap a photo of the MAC address so setup goes faster in store.
Swap Paths That Save Time
You can visit an Xfinity store for a one-for-one exchange. Bring the gateway and the power brick so the team can match parts. If you rent the unit, the exchange is routine. The equipment replacement page outlines returns and common timelines.
What To Expect After A Swap
After an exchange, connect coax, power on the gateway, and wait for a steady white LED. The xFi app walks through Wi-Fi name and password setup. If you set custom DNS or port rules before, jot them down and reapply once you’re back online.
Deeper Troubleshooting For Edge Cases
Edge cases can keep a good unit off. Heat, a failing wall outlet, or a line issue can all look like dead hardware. These checks help you pin it down.
Heat And Ventilation
Routers run warm. Stacking it under a console or inside a cabinet traps heat. Give it air on all sides; keep it off soft fabric. If power returns after a cool-down, plan a better spot.
Bad Outlet Or Loose Neutral
A flaky outlet can power a phone charger yet sag under higher draw. Test a different room on a separate breaker. If lights appear only on one circuit, call a qualified electrician to inspect the run.
Coax Issues That Mimic Power Trouble
Hidden amplifiers or damaged splitters can interrupt boot. Connect the gateway directly to the main coax line with no splitters. Tighten by hand; skip pliers.
Button And Port Checks
Make sure the rear power switch is set to on if your model includes one. Check the barrel jack for play; a worn jack can drop contact with small bumps.
LED Reference And Action Plan
Once the unit powers, lights tell the rest of the story. Use this quick chart while you test.
| LED State | Meaning | Action |
|---|---|---|
| Off | No power to device. | Recheck adapter, outlet, and cord fit. |
| Pulsing | Boot or firmware update. | Wait until steady; don’t unplug. |
| Steady White | On and ready. | Test Wi-Fi and wired speeds. |
| Steady Red | Error or no signal. | Inspect coax and service status. |
Care Tips That Prevent Power Headaches
Place the gateway in open air, keep dust off vents, and give the adapter a little slack so the barrel stays straight. Use a quality surge protector, but move to a wall outlet for tests. Label the adapter so it doesn’t get swapped with a look-alike from another device.
When To Suspect A Failing Power Brick
Failing bricks leave clues: a faint whine, a hot case at idle, or LEDs that flick on for a second then vanish. Another tell is a gateway that powers only while you press the barrel sideways. That points to either a worn jack or a loose plug size match. Try gentle pressure in each direction; if power flickers, replace the brick and keep the cable strain-free.
Protect Your Setup From Repeat Trouble
Mount the brick where air can move. Avoid daisy-chaining long extension cords. Keep the gateway off the floor to dodge vacuum bumps. Note the SSID and admin password in a safe place so you can bring a new unit online in minutes. A small label on the adapter with the model name pays off when cords get mixed during cleaning.
What To Say If You Need Help
If a swap or a new adapter doesn’t bring it back, note the model, serial, and MAC, list the steps you tried, and share any LED behavior you observed. That short list speeds up next steps, whether you visit a store or chat with an agent.