On a recent edit, there was a noticeable delay (probably 10 frames) on the video that played on the broadcast monitor (Flanders Scientific). Whenever I started playback from the first frame of the video, everything synced fine, but if I started from any moment before that, the lag occurred.
In addition to the other suggestions, note that your playback offset should probably be set to 1 or 2.
There is a slight delay in any LCD processing your video so you have to offset for that in FCP. I believe we have the offset in all our rooms set to 2 and we run all FSI monitors. The 17" might be a 1 frame offset, but I'll have to check on Monday when I'm back in the shop.
I discussed this at length with Bram and Dan at Flanders and if you really want to have all the technical explanation for the delay in the signal, feel free to call them. They are great guys.
Walter Biscardi, Jr.
Editor, Colorist, Director, Writer, Consultant, Author, Chef. HD Post and Production Biscardi Creative Media