Hey @gimbillinn,

Welcome to the Sonos Community and thanks for you post!

Do I understand correctly that you want both home theater systems hooked up to the TV and choose which one gets to the play the sound? Without removing plugs and cables, of course.

I would think that the solution would be on the TVs side as both sound systems would only be at the receiving end of the audio stream. Perhaps there is an update available for your TV - you can check this with LG directly.

Out of curiosity though, why do you want to have two surround systems with the one TV?

I have old surround system which consists of HK receiver front rear and satellite speakers that has been my main surround system for many years,few years ago I bought one of the first LG 65 inch oleds and yamaha NS 2000 surround and could easily change between them in the TV menu.My tv is now LG oled 65 type C2 ,connected to sonos ARC full system and with optical to the HK receiver and when I try to change from the sonos on the menu to the old system it´s not possible to use it without physically unplug the HDMI from the TV

CEC tends to automatically connect to the HDMI-ARC/eARC connection, regardless of you switching to the optical or TV speakers.  If you wish to use the optical instead of the ARC/eARC device, you need to turn off CEC (called SIMPLINK on LG TV’s).  CEC is quirky enough without it having to figure out that the TV has two surround systems connected. 

Thanks for the info.I tried to turn the simplink off,and off it comes but as usual when optical out is chosen I get about one sec before the TV turns it again on,it´s like fighting against windmills