I’d think it would work, try any device you have with a line-out connection to see if it does before spending any money.

If your turntable doesn’t have a built-in preamp then you would need an external one, make sure it offers a Phono input as you need both the boost in power and the equalization circuit to get decent sound.

On some TV’s, you may find the component port ‘may’ not operate without their being any video input alongside the audio… and the port signal shows ‘no signal’ on the TV screen (and no sound too), but some TV brands/model’s may work and what @Stanley_4 suggests in regards to using any line-out on a device you have lying around, just as a test, is also what I would try first, just to see if the port works, or not.

If it does work with audio-in from a mobile/tablet or MP3 player etc; then it should work with a TT and pre-amp.

Even it works you would have to power on the TV for the port to be recognized and switch to that input. Don’t think I’d want to have my TV on without a screen saver or something. Also some TV’s auto power down if no video to prevent screen damage. My suggestion is to acquire a Port (new or used) or you might find a good deal on a used Sonos Connect.

thanks!  Like I said it’s not an optimal idea, just possible solution to add a turntable to an existing Sonos system with no external inputs, like a Beam and Play 1 or 3 speakers.