@lrhawthorne 

As long as your Powerline kit has been fully installed - with the base unit wired to router and plugged directly into wall power outlet and the extender unit placed elsewhere in your home but also plugged directly into a wall outlet - you should be able to connect multiple devices to it via WiFi, including your TV, since your router's DHCP server can handle multiple connections.

One thing to check would be ensuring the primary Powerline adapter is connected to one of your router's LAN ports, and not directly to your modem. A modem (non-gateway) can only supply one connection at a time. Please also check whether the WiFi Powerline unit's Powerline LED is properly illuminated, indicating a proper connection between the main Powerline adapter and the extender unit.

Another thing to check would also be whether your iPhone is actually connecting to the Internet through the Powerline WiFi extender, or if it is using cellular data while simultaneously connected to the WiFi extender (without Internet). If this is the case, it could indicate that the Powerline connection between the adapters has not yet been properly established.

Please do not plug either of the Powerline adapters into surge protectors or power strips, as doing so will interfere with and/or prevent Powerline connectivity between them.

@lrhawthorne 

Thanks for the update. In that case, it is recommended that you make sure the firmware of your TL-WPA7510 Kit is up to date, as shown in our FAQ here: https://www.tp-link.com/us/support/faq/1419/

Please also ensure your TV has the latest update(s) installed.

You can also try changing the WiFi channel setting(s) from auto to a specific channel on each band to see if your TV prefers a specific channel within the WiFi spectrum, as outlined in our FAQ here: https://www.tp-link.com/us/support/faq/1418/

If the symptoms persist, please provide your TV model number and we'll gladly escalate this to our engineers for further information.