Picture flickers on and off when in camera mode only.

I've recently run into a very odd problem. When my camera is in Camera mode, the view on the LCD and through the Viewfinder is almost black. You can tell the camera sees something because there will be rough stretched shapes occassionally. But mostly it looks like a black screen with flickers of white lines. If I record like this the image comes out exactly as seen through the lcd or viewfinder. The audio is perfectly fine. If I play with the zoom function, it will occassionaly flicker and then a normal picture will come through. It may stay like that for an hour, or for a few seconds. It seems very random.

I thought it might be faulty power, but it seems not. A different battery, plugged into the wall with no battery, same problem. Different tapes, same thing. No tape in, same thing. In player mode it works just fine.

I have no idea what is going on here. I thought maybe the heads needed cleaning, but since it's distorted without a tape even in there, and the view is messed up, not just the resulting recording, that can't be it.

Any ideas?