Why do I have a dark streak?

I have a 6" dark streak across the top of myMitsubishi 65" DLP. What's the fix?

crwdns2934089:0crwdne2934089:0 crwdns2934093:0crwdne2934093:0

crwdns2934109:0crwdne2934109:0

crwdns2889612:0crwdne2889612:0 1

crwdns2942205:01crwdne2942205:0:

What model is your TV?

crwdns2934271:0crwdnd2934271:0crwdne2934271:0

crwdns2934285:0crwdne2934285:0