The toner cartridge is improperly installed or is defective.
The HV contacts are dirty or the HV PCA is defective
– Clean the HV contacts or replace the HV PCA.
LJ 4L and 4P: The HVPS, AC power module, and DC controller
are all on the same board.
The DC controller is defective.
The laser/scanner cable or assembly is defective.
5L, 5P, 6P, 6L
Light is leaking into the printer
IIP, IIP+, IIIP
The fiber optics cable is defective.
4L, 4P, 4V
Light is leaking into the printer.
278 – Image defects