Hey guys.
My rig has a home theatre box running Windows 7 (RC 7100) for media center, a Nova 500 DVB-T twin tuner and everything gets routed through my Onkyo TX706 amp.

The amp switches all inputs (WII, DVD player, Video, Zinwell Freeview) to the single HDMI cable to my full 1080p PZ850 Panasonic Plasma.

All good so far, however I have noticed that sometimes when I power up everything using my harmony One remote with HTPC selected I sometimes get grey snow on the plasma instead of an image.  I have to switch one of the other sources, say the WII, wait for the TV to lock onto that and display the upscaled 1080i picture generated by the Onkyo, then switch back to the HTPC.  Sometimes I have to do this twice.  The HTPC has a Nvidia 8600 GTS putting out 1080p at 50 Hz.  I have tried 60 Hz without seeing any difference.

My thoughts are ;
It's losing HDCP via the AMP and therefore refusing to shown an image?

The 1080p signal is confusing my amp at power up as it normally tries to upscale any video input to 1080i?

Thoughts please.