Maybe I don't understand the last post from the OP, you set your camera on Manual 1/128th power correct? Please set your camera on Manual as well and shutter speed of 1/250th and fire a test shot. with a high shutter speed you kill all the ambient room light and see flash light only. Now you can really see what your flash is doing. BUT MAKE SURE IF YOUR FLASH IS ON MANUAL YOUR CAMERA IS AS WELL FOR ALL TESTING!