Apple TV connection problem

I just bought the latest ATV and connected it to my office TV (LG 720P HDMI) for a test and it worked great. Then I moved it to my main TV and it doesn't. Here's my equipment:

• Samsung HLN567W DLP 720P TV set with DVI input (Note this is a 9 year old DLP that predated HDMI)
• Onkyo TX-SR606 Receiver (HDMI)

I currently connect Sony Bluray and DirecTV boxes via HDMI to the Onkyo; the Onkyo then outputs HDMI through an HDMI->DVI adapter to the TV. Works perfectly.

So I connected my new ATV the same way...and the TV shows "unsupported mode". I thought it may be becasue the ATV was set to 1080P so I took it back upstairs and set it to 720p. I also set the Onkyo to down-res all HDMI inputs to 720p. No change, still shows unsupported mode.

I'm at a loss what to check next...any ideas?

Thanks!

Only guessing - it's an HDCP issue and don't know of a way around it.

That's a good thought but the TV has that capability. In fact, it was that very issue when I bought my first HDMI components that caused a problem, but it was still under warranty (by 2 weeks ) and they replaced the video board and voilé it worked great.

So, I'm thinking probably not but...

As bobtomay pointed out its a handshake issue that I see on a monthly basis with older gear and monitors with DVI some equipment plays well others do not , just because there are standards does not mean every mfg follows them .

Sigh...ok thanks. Guess the ATV goes back upstairs until the TV finally dies.