Facing TV Problems? Ask a TV Technician.
Is your model the HL5687WX/ or the HL5617WX/ ?? There's one extra number in your TV's model that shouldn't be there.
There isn't an EASY adjustment...but there should be one for the "light tunnel alignment. I just have to figure out if the HL56187 has those instructions, or if I have to find another model clearly showing the 2 mini torx adjusters on top and back of the light tunnel.
That's why you have that black shading...unless one of your mirrors got hot enough to lose its adhesion. The tricky part..it could be you have the HL56187 OR it could be HLS 6187. Both are valid models, but Samsung usually only used 4 numbers in the DLP TV sets.