LCD cable maybe loose. LCD show black bar when power supply to LCD is present but not getting data from main board. usually firmware missing or power to no power to main board due to burned fuse is the cause of black bar. If it prints fine, it can be problematic firmware or loose LCD cable. (Don't play with LCD cable with printer power on, unplug the printer before doing anything on main board)
(Da Vinci 1.0, Jr. 1.0 RAMPS, miniMaker) X4, (Creality CR-10S, CR-10 mini, Ender-3) X4, Anycubic MEGA X4, Anycubic Chrion X1, ADMILAB Gantry X2 (MonoPrice Maker Select V2, Plus, Ultimate)X4--Select mini X1, Anycubic photon X4, Wanhao duplicate D7 X1.
iNSTONE Inventor Pro X2, CTC Dual X2, ANET-A8, Hictop 3DP-11, Solidoodle Press, FLSUN I3 2017X1