please help anyone! panasonic s60 black level issue

[gsosa]

Ok so I bought a panasonic s60 plasma off of a friend of mine. The tv has roughly about 4,000 hours on it, the colors are great and so is the clarity but the black level on the tv is not that good. My brother has a cheap sanyo lcd and it has darker black levels than this tv. I thought plasma were supposed to have superior black levels, could there be something wrong with the tv? I have tried calibrating the tv a little and it did not help much. Please if anyone has any suggestions please reply. Thanks l