I'm seeing simular problems with my V2700. I have an OPPO 970HD and a Comcast DVR connected via HDMI with HDCP. It will work fine from a cold start for about an hour then the V2700 loses sync or something - the screen goes black. I have an HTPC connected DVI to HDMI too, and it never loses sync, works great.
My problems appear to be HDCP and heat related. If I turn the v2700 off for 15 to 30 minutes HDCP enabled devices work normally for about 10 to 15 minutes. If I flash the OPPO 970HD with an older hacked firmware that removes HDCP then it works great without problems, never loses sync.
I tried calling Yamaha support, and the guy I spoke with was not very sympathetic. He said I should carry it back to the Magnolia store and have them confirm my problem - even though they aren't an authorized repair center (I've had it for more than 30 days so I can't exchange it). I asked him what I needed to do if they were able to confirm my problem is with the v2700, and he said I would need to take it to a repair center. I told him there isn't one within 100 miles. He said I'd have to ship it to a repair center at my own expense. The guy acted like he really didn't care at all. He said he hadn't heard of any problems with the v2700's. He also said he wasn't convinced it was a V2700 problem at all - it was probably my devices.
I have since replaced all my HDMI cables with monoprice cables. I've even replaced my HDTV with a KDS60A2000. The exact same problems exist.