TV black & white is green & white -- HELP !!

Hi all: I'm experiencing a problem with my Orion color TV (19"). Basically the color is ok, but the problem is that blacks are not black, but green. Not a tint adjustment problem (skin tones are good).The TV has a greenish glow when it's on and if I were to watch a black & white movie,it would be green and white. Hope this explains the problem well enough !! I suspect that I may have to take it in to a repair shop for adjustment, but was wondering if anyone has an idea as to what is wrong. I'd like to have a little more info. before I take it to a repairman. Thanks in advance for any info. on this problem. Ray