Canon EOS 5D Mark II - Has Power But Not Processing Images

[mr.mike]

Wondering if anyone has experienced the dreaded Canon EOS 5D Mark II with the Black LCD Screen Syndrome? Just picked one up on Ebay at a reasonable price. Of course with issues. From what the previous owner tells me, the camera powers up, but no images appear on the rear screen. In addition, he tells me that none of the buttons function. I haven't gotten it yet so I can't provide a more accurate description of what this camera is all about. That said, I'm wondering if anyone has had a similar experience with this model? The camera is very clean and doesn't appear to have been abused in any way. But of course we can only guess at this point. I'd be interested in hearing from you.
Mike