Here is a canon MV530i camcorder. I Charged it up, cassette is in and ready to go - but it’s only showing black, both on the screen and in the viewfinder. We tried recording a bit and we only caught audio, no video. Pic is for reference - the viewfinder looks much the same. It’s not giving any kind of error message or anything (other than the red symbol which indicates I haven’t inserted a backup battery).

when this happens its the aperture being stuck or the sensor not sending the video.

What you could do is disassemble the camera and then simply reassemble it and see if it did anything, chances are it’s a disconnected cable.

Everything is with the camcorder though so you will get a bargain once you have fixed the cable.