ok, I just got a new 13" MBP to replace my 2006 Core Duo Macbook. Any help you may be able to offer would be greatly appreciated. Here's the problem: I used to connect my macbook to my projector (Panasonic AX-200) using an mini-dvi to DVI adapter, a DVI to HDMI adaptor, then a 10m HDMI cable to my projector. This worked flawlessly, both for mirroring and extended display. When I got the new machine this week, I bought a cheap mini displayport to HDMI adapter off ebay to go with it. Using the same 10m cable, this would show the extended desktop for about a second then go blank, then repeat this cycle indefinitely. I then tried using a shorter HDMI cable to check the adapter and mini displayport. This worked perfectly. However that was with a 2m cable, I need a 10m run for the cable. So, I bought an mini displayport to DVI adapter today, hoping that the cheap ebay adapter was the source of interference or impedance. However, using the same setup as my macbook, albeit with the new adapter, it doesn't display an image at all. Again, using the 2m cable works perfectly. The video settings are 720p as they should be, and I've still got the macbook and checked that it still works, so my question is for signalling geeks I suppose. Is there a power issue here? Is the mini displayport just outputting less juice than the mini dvi? Do HDMI cable impedances vary significantly?