No images but records sound
To start ensure that you removed the cover from the lens.
Also remove battery and put it back in place to reset the camcorder.
If you get only sound on playback, connect the camera to a computer or TV, or play the tape on a different camera.
If you get picture in there, then the camcorder is recording, but the video playback does not work because of a faulty LCD display.
If when you play back the movie on a different camera, or using the compute you still get no picture then the camcorder is faulty.
Faults that can cause black screen can be:
Faulty CCD sensor.
Faulty controller board.
All this faults are not easy to diagnose and fix, if there is a fault , then it is better to take the camera to a repair shop.