Tracking problem with JVC camcorder.

[The-Geek]

Hi am not exactly a newbie i have been doing some video, like chroma-key, editing. I have a old JVC GR-S70U S-VHS camera that my dad gave me and I would like to use it, but when ever i boot it and go to the recording screen the screen flickers up and it takes it a couple of minutes for the video to normalize, but when i record the video it is unplayable, even the audio is gone, i tried cleaning the video head, it still works fine but that did not solve the problem. Lastly when ever i set the shutter to 1000, and 500 and look at windows or at my monitor black patches appear and the will not go away until I turn the shutter to 250.