OK, Stuart: I know this is considered a Takky ... but I was recently confused by something I read on MicroMac: they indicate an LC 575 (or any 5xx for that matter) can be upgraded to an LC 5200 by a simple logic board swap. What!?! If that's true, why again doesn't the Pythagorean theorem work here? If B works in A and C works in B, then C should work in A. Right? It would seem that I should be able to use the 5200 logic board in the CC with the ease of using the 575. So why isn't it this easy (before I run out and buy a 5200)? Sorry if I'm treading over worn ground, but I did a search and didn't find much pertaining to the 5200 upgrade in particular. I had just never heard the 5200 in 5xx was possible this easily before.