Hello Everybody. Just wanted to say thanks to all that have advised about this issue with the Nikon F3. I hada a beatiful body some yars ago and sold when I need it to fund other projects. This weekend I got a nother body, with good looking condition, proceed to test it with fresh batteries without a roll and found the exact same issue reported here: 1) the shutter cocks and the switch is on. 2) The shutter release button does not fire when pressed. But id does activate the light meter, I can see all speeds and all apertures in the viewfinder. 2) the mechanical release lever works with the switch on or off (3) the only way to make the camre fire, is by pressing the DOF button. This works with the switch on or off 4) the DOF function does not work when you press it. (It fires the camera only) 5) sometimes, the camera fires while cocking the shutter (1st tme after 5 shoots, 2nd time after another 10 shoots). I will test it with a roll, it´s not pleasant nor anatomic to fire with the DOF button. but mainly I would be ineterested in testng the speeds, the leight meter accuracy. I take note of your diagnostic and recommendations; a CLA is necesary. Thank you all!