Recently I had acquired a Colecovision, and hadn't gotten around to plugging it in because I had no games. Once I got some games and tried to play, the CV's RF output had a green tint, and looked as if I was playing on a GameBoy screen. There was no color, and all the graphics were just various shades of green! I tried to reflow solder on the RF board to no avail, de-soldered and checked the RF board and the components underneath (no difference), cleaned the power switch (which did not work) and even tried poking around the graphics chip and saw absolutely no difference in color whatsoever. I'm at wits end trying to figure out what is wrong with this CV.
Attached below are a couple of pictures from the system on my Trinitron TV. This also came up on a flat screen TV as well.