Originally posted by twitch "Mirror flop" was a widespread problem for early K-5's caused by faulty mainboards.
I started getting mirror flops after the camera was almost 2 years old and only after everyone started posting about it :-(
My K-5 gave up after one long mirror up with that black frame, then a few more normal shots, then showed an empty batter symbol. Removing and replacing the battery returned operation to normal until I pressed the shutter - nothing, and low battery symbol again.
CRIS said it is the mirror box motor - $258. Wainting on parts...