Thanks for the suggestions. I do need to find fresh batteries for it, but I still would expect it to work (mechanically) in manual mode. I tried Randy's suggestion, but the mirror only releases when it's good and ready.
I contacted Eric (Mr. Pentax) and there's no doubt in my mind that he runs a good honest business. I'm just trying to decide if it's worth $70+ to have it fixed, when I can pick up a perfectly functioning one from eBay for $20 to $30 less (and an extra lens in some cases).
Actually, for the price, I would have my pick of older, entry-level SLR's...