Jill; I don't know how many times I've gone to a store to purchase a replacement part (as recently as this weekend for a filter part for my pool) and was told, "Sorry, that model is obsolete, they don't make them anymore". Even some close-out items that are on sale in the weekend newspapers are cheap because the product they are selling is "obsolete" and a new model (or a new chip) has replaced the "old one". The differences with obsolete chips ... is that they ain't cheap!