Epson C117001-N - DFX 5000+ B/W Dot-matrix Printer Service Manual page 162

Table 5-7. Printer Mechanism Repair (continued)
Symptom
A particular dot does
not print.
The print is too light or
print density is not
uniform.
Printing is performed,
but the printer does
not feed paper or
does not feed it
correctly.
The ribbon feed (RF)
motor does not
operate.
Rev. A
Cause
The printhead is
defective.
The printhead is
defective.
defective.
The parallelism value
is incorrect.
Foreign objects are
lodged in the paper
path.
The PF motor is not
driving the gear
properly.
The PF motor is
defective.
The ribbon cartridge
is defective.
Foreign objects are
caught in the gears.
Checkpoint
Measure the
resistance. (Refer to
Figure 5-4 for details.)
Check whether a
dot wire is worn.
Check if the tip of a
dot wire is worn.
Print density differs
at the right and left
sides of the page
(darker on one side
than the other).
Visually check the
paper path.
Check whether the
PF motor pinion gear
rotates smoothly
when rotated
manually.
Measure coil
resistance for the PF
motor. (The correct
resistance is
approximately
2.85 ohms.) Also
check the PF motor
drivers.
Remove the ribbon
cartridge, rotate it,
and check whether it
feeds the ribbon
normally.
Check whether the
ribbon driving gear
rotates when the
cartridge is moved
manually.
Troubleshooting
Solution
Replace the printhead.
Replace the printhead.
Replace the
Perform the
parallelism
adjustment, as
described in
Section 4.1.5.
Remove any foreign
substances.
Check backlash
between PF motor
pinion gear and paper
feed reduction gear.
Replace the PF
motor, and if
drivers are bad,
replace main board
at the same time.
Replace the ribbon
cartridge.
Remove any foreign
objects or replace
darnaged ribbon feed
mechanism part (the
ribbon feed select
gear, ribbon feed
transmission gear, or
ribbon feed gear).
S-25