I have been using the model AC1750 and when I started having problems with it, purchased the AC2600.  I unplugged the 1750 so that it wouldn't interfere with setting up the new 2600. I plugged it in and I have power.  It shows up on my network list.  It says "open" but when I try to connect it says no internet open.  I assumed that since I've successfully had the 1750 working that the 2600 would be no problem.  I have Tether on my cell phone but I can't continue with the setup until I resolve the no wifi problem.  Any suggestions?