I get guaranteed blank Mamiya RB67 negatives everytime I leave the little dial on the lens in "Mirror Up" mode instead of "Normal" mode and just use the body shutter release instead of a cable release on the lens. There is no safety interlock warning of this error. The camera sounds like it is working perfectly but the shutter never opens.
Be sure to check the mirror up switch on the lens?
Anyone can make a Digital print, but only a photographer can make a photograph.