Bad Cable Input

Try using your RCA imput to see how the picture looks compared to the tuner picture,is possible your tuner imput is bad,make sure the conector is not loose,the overall picture should look different but not fuzzy all over,using a dvd picture thru the aux (rca)imput should show you the difference.If the conector is loose only it could be repaired but if it is solid the tuner might be bad and it will need to be replaced along with any board it might be mounted to.Let us know how it goes or if you need more information.