HP M750 series

Problem Sample Cause Solution
A horizontal white line appears on
the page.
Repetitive horizontal white
lines appear.
Use the repetitive defects ruler to
identify the dirty roller. Clean the
roller. If the roller cannot be cleaned,
replace the roller.
Horizontal scratches are
present on the photosensitive
drum.
Replace the print cartridge of the color
that matches the defect.
Scratches are present on the
circumference of the ITB.
Replace the ITB.
Image in a particular color does
not print in the correct color.
Poor contact exists in the
primary charging bias or
developing bias contacts
between the print cartridge and
the product.
Clean each contact of the color that
produces the missing color. If the
problem remains after cleaning, check
the contacts for damage. Replace any
deformed or damaged parts.
The print cartridge (primary
charging roller, developing
roller, or photosensitive drum)
is defective.
Replace the print cartridge of the color
that matches the defect.
The imaging high-voltage
power-supply is defective (no
primary charging bias or
developing bias output).
Replace the imaging high-voltage
power-supply.
The laser/scanner unit is
defective.
Replace the laser/scanner assembly.
Dropouts appear.
The secondary transfer roller is
deformed or has deteriorated.
Replace the secondary-transfer-roller.
The primary charging roller,
developing roller, or
photosensitive drum is
deformed or has deteriorated.
Replace the print cartridge of the color
that matches the defect.
The fuser roller is deformed or
has deteriorated.
Replace the fuser.
The transfer 1 high-voltage
power-supply PCA is defective
(no transfer 1 bias output).
Replace the transfer 1 high-voltage
power-supply.
The transfer 2 high-voltage
power-supply PCA is defective
(no transfer 2 bias output).
Replace the transfer 2 high-voltage
power-supply.
The toner is not fully fused to the
paper.
The fuser roller or pressure
roller is scarred or deformed.
Replace the fuser.
The fuser control circuit is
defective.
Replace the low-voltage power
supply.
The thermistor is defective. Replace the fuser.
The fuser heater is defective.
520 Chapter 3 Solve problems ENWW