Perform a hard reset to set a good reference point. Please see the attached photo with instructions for the procedure.
If no improvement, remove the lens, memory card and battery, set the mode dial to M (manual), and switch the camera to the ON position. Allow the camera to sit idle for 20 minutes. Then, switch the camera to OFF, re install the battery, memory card and lens, switch it on and try to fire the shutter while still in M (manual) mode. If the viewfinder is still black, remove the lens, put the camera in manual and while observing the mirror press the shutter button and see if there is any movement at all. Please let me know the result
Please keep in mind that my diagnosis & solutions provided are directly dependent on the accuracy of your description of the problem. As with any "do it yourself" fixes, success is a "team effort", since I can't see or touch the camera, and relies on the customer's manual dexterity and ability to follow the instructions well. If the "do it yourself" approach doesn't work out for you and you need conventional repair, please let me know.
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