arc ultra loses hdmi sound

I was on with support for about 15 minutes this morning. It's not the cable. I'm going to pick up a new arc and a new arc Ultra, the strange thing is the ultra was working for about 3 weeks and now it's not working with the TV. I can actually get it to work but then the Sony clicks back to TV speakers. It's dropping the signal. We tried another cable that wasn't the answer. So what I'm going to do is I sold my old Arc. I'm going to hook up the ultra. If it doesn't work, I'm going to hook up the regular Arc and see if this solves problem is does I'll take the ultra back and that's it. I'm not going to go back and forth

​@TpaTurk this seems a different problem from the one discussed here. For me (and I think others too) the Tv remains connected to the soundbar, but the soundbar stops emitting sounds (and even the sonos app stops detecting input). This typically happens when the sound mode goes from stereo pcm to dolby 5.1, usually with an external source (appletv or sky box).

Well nothing has changed but I just tried an Arc and  new Ultra I think it is an issue with the actual HDMI earc output/input of the TV. It may have a short, it actually sees the ARC and Ultra bit the  goes back to TV speakers about 5-15 secs. Also Sonos app cannot complete setup 

Optical adapter arrived today. It doesn't solve the issue so if you were planning to buy one I'd suggest to hold off. At this point the issue seems mostly unrelated to hdmi, and more to do with the way our sony tv passthrough audio to external receivers.

I just need my Sonos sound bar to work again. As long as that works I am good 

Are you sure ? I have the same problem and for me it is clearly related to Arc Ultra as the optical interface worked fine with the Playbar. 

The problem is 100% with the Ultra and old-ish sony bravia tvs. No matter whether hdmi or optical connection is used, the Ultra will lose sound when switching enough timed from stereo to surround mode.

Well I don't know about that. My old Sonos Arc worked fine for years. The ultra worked fine for 3 weeks. Then all the sudden I ran into this issue. I actually returned the ultra and bought a new Ultra and a new regular Arc and had the same problem with both. Right now I'm thinking month it could be my TV Arc output input went bad.. I'm ordered a Sonos optical adapter. See if it works but my ultra did work for weeks before all this.

​@TpaTurk I believe your problem is completely different from the one discussed in this forum. You get no sound at all (if I understand correctly). The problem discussed here has to do with sound generally working, but sometimes stopping when audio input switches from stereo to dolby. If this is not what you are experiencing, I'd suggest to maybe start a new topic , otherwise this can get confusing.

Just to update on my issue with Sky and sound drops, we bit the bullet and upgraded to  Sony Bravia series 8 which has an Earc connection, and I am no longer getting g the sound drops. This works both with Auto and Passthrough mode selected, although I have left it on Passthrough so when a Dolby Digital 5.1 is available it will auto switch to that mode. I am also now not getting the big volume changes when selecting different channels.