Airport Extreme ethernet port lights flashing but won't start up

I can confirm this was my problem as well. The Ethernet ports on the back of the unit would flash green for half a second and then fade out, then flash, then fade, and so on. Replacing the power supply fixed this completely.

Unfortunately, flashing Ethernet port lights are almost always a sign that a component in the internal power supply on the AirPort Extrme is failing, or has failed. Soon, the lights will not be on at all.

Time to replace the AirPort Extreme, as Apple will not offer repairs.

Don't be too quick to discount the unit. I thought mine had died after seeing flashing lights on each port. I put a multimeter on the power supply and it was only reading 6V instead of 12V. I found a 12V power supply from another modem that fit and the Airport sprung into life again!

Wurzz is right. Definitely a power issue. I Had the exact same problem. Gave the external power supply a good whack, and it sprang to life. Never underestimate the power of a good whack.

Hi RShelton, Wurzz is definitely right. I just had the exact same problem with my 2007 airport extreme n. Fixed by simply finding a compatible power adapter. Just make sure the output is 12v and no more than 1.8amps--or identical specs as the original airport extreme power adapter. Mine now works like a charm and is actually faster than before--probably because it was under powered due to a faulty power supply. One thing I noticed was when I plugged the old power adapter into a power outlet the adapter would literally make a hissing sound--which would continue even when unplugged from the power outlet. The adapter was definitely fried.

So before you go out and buy a new airport extreme--or throw away your old one, double check the power supply adapter. Will save your close to $200 for a comparable wifi router. And you can buy compatible power adapters from Radio Shack or Best Buy for about $10-$20.

As a side, I spoke with an Apple support rep and she mentioned that you can get your defective wifi routers replaced under warranty if any mac you own that's covered under apple care was purchased within two years of the airport extreme (before or after). That was very good to know.

Thanks Wurzz! This worked perfect.