721 blacking out on screen but recording

To rewind this a bit, I am in Alaska and can not get a good enough shot at 110. For whater reason E* does not put the software or EPG on 119, only on 110. Well I was able to get the software download from a dealer who has a 2M dish and can get a signal from 110, download the initial software and away we go. I have a dish 300 with a dual lnb and both outputs going into the 721.

Everything seemed fairly normal, pause, ff etc. Guide looked good, programing was fine. Then while watching one show while another timer was recording something else I hit PIP and the pip window opens, fills with the main on-screen program goes black. The svideo tv screen goes black and there is no audio. Very curious. I cant swap and if you hit cancel or view the proram banners says "Unknown Record". Huh???? A power down (with the remote) seemed to clear it up. Other PVR functions are working, I can see the menus, call up the guide etc. Then it happened again. The really weird thing is that we were recording DS9 but it went black on the tv. We left it alone till the end of the program and lo and behold, it was recorded just fine. We could watch it recorded, but were unable to watch it live.

It am not 100% sure it has to be recording for this error to manifest. Last night we were watching, swapping between pips and with recall on one tuner and the main screen went black while the pip was on. No swap but a remote power off triggered a system boot. It went through the hard drive verify and acquireing info from the satellite. Appeared to be a full reboot to me.

I figure this could be:
some artifact of my 119 only setup, like can't dl software
no switch, just dual lnd into dual inputs on 721
a bum 721 with heat or other problems (it is in a good spot)

Any thoughts on this one?

thanks...marshal