good day, i just can't seem to win. on our newest phase back i am seeing a single line down the scanned image (parallel with the CCD movement). it is seen on the RGB image but when flipping through the various channels it is only found in the red channel. i've cleaned the CCD half a dozen times. i've cleaned the lens, filter and i am still seeing this line. is it dust? can you offer various cleaning tips? i really can't see anything on/near the CCD. i even used a magnifying loop to look for dust... and saw nothing.