Problems with Sony DVD Burner after Replacing Tray

I recently replaced the tray on my Sony DVD Burner(Sorry, don’t know specific model, but I purchased it recently.) and since it has been failing at functioning. Mechanically, it works fine - the tray moves in and out through the full range of motion, and the laser and CD motor move up when the tray recedes, but it does not recognize discs placed in it, and, in fact, the computer is not seeing the drive at all. Is it possible I might have accidentally bumped something whilst replacing the tray?

Much obliged.