I use the wheel all the time, so actuaily I cannot imagine it does not work properly.Difficult then, I would test the mouse wheel in other applications, and if necessary try to obtain another mouse.
Yes, I had tried them but always the same step wide no matter what I enter in the settings. I cannot see any difference.In the View menu you have zoom options using keyboard + and - which might be worth testing, and as they should use the same zoom settings might provide a temporary solution