Hi,

Sorry to respond late.

As my knowledge, the extender won't affect the performance of the main router.  Back to your case, we can do some troubleshooting and try to fix it.

May I know how did you setup the RE650? With the web UI or the WPS button?

It is suggested to reset and reconfigure with the web UI; and please setup different wifi name for the extender. 

Note： How  to configure it: https://www.tp-link.com/en/support/download/re650/#video or https://www.tp-link.com/en/support/faq/1400/

Besides, you can update the firmware to the latest one and give it a go. 

https://www.tp-link.com/en/support/download/re650/#Firmware 

Good day. 

DonTurco wrote

Hi,

I bought RE650 and set it up but when when the extender is on my Asus DSL-N66U keep drops its wifi signals. I mean wifi signals from my dsl modem turns off and on. When I unplug the extender, everything works fine on modem. Any ideas?