Macybaby, I'm going to remember the shim trick for the future! My recently acquired 730 had the same issue (and it has several others, all waiting in the wings for solutions), and I took a chance by very gently and slowly and carefully inserting a small flat blade screwdriver between the top and the head and lifting, until it finally popped it off. Gave it a little squirt of Liquid Wrench where it looks like the catch is, too. It's still tight but I can get it open now by placing my palms on the back of the top, fingers on the front, and pulling up.