WRT120N Loses connectivity WHEN I connect the modem

Registration date
Monday September 7, 2015
Last seen
September 7, 2015
- Sep 7, 2015 at 04:55 PM
Ok this is weird one.

My WRT120N seems to connect fine to any device UNTIL I connect the router to my internet connection and then the connectivity signal goes in and out. I've tried with multiple devices and it seems that the issue is coming from the Router itself.

So to be clear. Until I connect the Cat5 cable into the internet port of the router, I can connect to the router via wifi or hardwired without an issue (but I dont have internet). As soon as I plug in the cord for internet, the wifi AND hardwire connection come and go about every 30 seconds but I do have internet when its plugged in. I've tried a hard reboot but that did not work. I'm currently reinstalling firmware but I doubt this will help.

Any ideas?