Panasonic KX-FL612CX - 6.5.7.2 Vertical Line Issues; Dark or White Vertical Line Resolution

6.5.7.2. DARK OR WHITE VERTICAL LINE
Note:
When wiping the lower glass, reflecting mirror and LSU lens, use a dry and soft cloth.
CROSS REFERENCE:
LSU SECTION (P.137)
89
KX-FL612CX / KX-FL612CX-S