Finally, confirmation I'm not going mad !
I have had this exact problem between my ES6800 and my HT-5500 ( issue was also evident with my D5100 ).
Here's what I've tried to resolve the issue so far :
- Tried connecting via SPDIF
- Tried multiple HDMI cables
- Changed TV input sources
- Firmware upgrades
Still experiencing sudden drops. I thought this was only evident via ARC but it seems to also affect SPDIF connections.
I have a ticket raised with Samsung, this has been ongoing for around a month. I even thought that there could have been some Electro Magnetic Interference causing this problem ! TV is wall mounted.
Anyway, firmware update ( for both TV and HT ) from 05/10/12 stabilised things for a few days then it started again. Yet another firmware update from 10/10/12 and things have stabilised again. This is a strange once. Sammy calling me back for update in 2 weeks.
I would try the latest firmware update. Let me know how you get on ! - I'm glad I'm not the only one here !