Extreme setup problems

Question

I hope that someone can give me some advice in doing something that I thought would be easy to do (I dare not tell my non-Apple friends that I am having this problem, as I told them it would of course be easy to do because it's Apple!).
In an attempt to overcome some problems with signal strength and interruption, I have just bought a new dual-band Extreme to replace an old-type Extreme. I connected the new Extreme in place of the old one and connected it to the internet as before (Ethernet to router), and powered the router off and on, with no equipment changed except for the Extreme.
I then turned Airport on, which showed a new network, which I selected, then I opened Airport Utility (5.4.1), which showed the new base station. I selected the option not to switch wireless networks, and it then showed a window with a suggested Airport Extreme Name, and I filled in the Aiport Extreme password, as before.
It then gave me 3 options: Create new Network; Replace existing base station; or Join current network. I chose the middle option (replace base station), and it then asked me to select the device or network to replace, so I chose to replace the previous base station configuration (as opposed to the previously used network). It then showed me the Internet Setup details, which were correct, and I added the previous password.
Then it showed the Summary page, which was as before, including the network name as before, except that the Airport Extreme name was the new one. I clicked on Update, the Extreme restarted, and its light went solid green. But, when I turned Airport on, there was no sign of anything, and iStumbler also saw nothing.
I then removed power from Extreme and modem for 15 minutes, but nothing changed on reconnecting. I have tried this whole process three times yesterday, and although I can't swear that I did everything exactly the same, the end result was always the same (but this time, I wrote everything down and took screen shots before starting and at every step). When I removed the new Extreme, and replaced it with the old one, everything immediately worked perfectly again, and when I reset the new Extreme, iStumbler can see the 2.4 GHz and 5 GHz networks with their default names.
To me, I seem to be following logical steps, and I would prefer not to have to scrap all settings that have been in use for 4 years and start again, in case nothing works even with the old Extreme. What stupid thing(s) have I done wrong, please?

Answer 1

Welcome to the discussions forum colinatascoli.
To me, I seem to be following logical steps, and I would prefer not to have to scrap all settings that have been in use for 4 years and start again,
You haven't done anything wrong and you did follow logical steps, but the "replace an existing base station" function has never worked for me either.
When things like this don't work right away, sometimes you're better off scrapping all your settings rather than spend time trying to figure out what's wrong. The good news is that your previous Extreme still works so you can copy all its settings, even if you have to enter them all again manually.
I'm a bit confused about your configuration. Is your router different from your Extreme? Assuming that's the case, you were right to power your router off and on, but some ISPs require more than that. Is it possible your ISP is using access provisioning? See this KB article: AirPort Base Station: ISP provisioning may prevent Internet connection via broadband (cable or DSL)
Also, if you're using an external router, such as if your gateway equipment is a combination modem / router, your Airport's connection sharing should be set to "off" (bridge mode).
Try powering your external modem / router off for a longer period of time. The reason for the power down is to give it enough time for its memory to reset - some require only a moment, but I've heard of some that require several hours. Some have a tiny reset button. Still others have an internal battery that has to be removed.
Hope this helps!