This is a new one to me….

I have purchased 2 new routers, one being used as an AP.

The main router at the adsl point works great, however when I connect and plug in one of the ethernet adapters, it causes problems with the broadband.

The router keeps saying ‘No Internet’ and wireless devices connect and then disconnect, when I remove the ethernet adapter, after a couple of the minutes the internet connection resumes.

Any ideas?

The 2 routers are Netgear N300, DGN2200 and the ethernet adapters are also NETGEAR XAVB5221-100UKS Powerline Adapters.

Are both devices trying to assign IP addresses to devices?

Not sure, how would I check? I have not used ethernet adapters before.

When you say disconnect – it that a laptop losing internet and the router ADSL light stays on? If the ADSL is dropping it’s more likely a duff cable or duff router causing a noisy and unstable signal.

If it’s just the laptop, I would check that the secondary router has all ADSL settings turned off and the WiFi setups as Access Point if possible, make sure only one of the routers is giving out DHCP and that gateway IP addresses are correct.

I have a laptop connected to the router via a cable (running the netgear genie software) and as soon as I connect the ethernet adapter to the router and electrical socket, the internet connection is lost.

Yes the ADSL light stays on, but the genie states no internet and nothing works/connects to the web.

At this point I have disconnected all other devices, so its only the above connected.

The problem is the new AP not the adaptors – it’s becoming the DHCP server when plugged in and assigning a different IP range to the guests by the sound of it.

Disconnect it from everything, plug a PC into it with a cable and configure it as a wireless bridge, ADSL all off etc. – then when you plug it in it will just act as a wireless access to the network provided by the main router.

Mains adaptors just bridge by default, at least every one I’ve seen do, so everything you plug into the far end appears to be plugged into a port on the main router.

Used a similar setup in the past with a DGN2200 router. No issues there. Regarding the ethernet adaptors, are they just powerline adaptors or can they be configured as routers / wireless APs etc?
Sounds to me like there’s two DHCP sources on there.

Yes the ADSL light stays on, but the genie states no internet and nothing works/connects to the web.

At this point I have disconnected all other devices, so its only the above connected.

Yep, that sounds like two DHCP sources, follow Brassneck’s advice. DHCP is sometimes a separate menu option, but normally just a ticky box to turn it off.