Service manual

4-12 Troubleshooting Rev. B
Confidential
Dots are missing
occasionally.
The head FPC may be
bad.
B Check the continuity of the
head FPC.
Replace the head FPC.
The print head unit
may be bad.
B Check if there are paper
particles or ink on the tips of the
dot wires of the print head unit.
Remove any paper
particles or ink, or replace
the print head unit.
The print head unit
may be worn.
B The cause is none of the
above.
Replace the print head
unit.
The character
width is
incorrect.
Paper particles or
foreign substances
may be attached to
gears, belt driving
pulley, or the belt.
B Check if any paper particles or
foreign substances are
attached to the belt driving
pulley, belt tension pulley, and
belt.
Remove any paper
particles or foreign
substances.
The gears, belt driving
pulley, or the belt may
be damaged or worn.
B Check for wear and damage
in the belt driving pulley, belt
tension pulley, and belt.
Replace any worn or
damaged parts.
Paper is not fed.
(Printing is
performed on
one line.)
The operation of the
paper supply may be
incorrect.
A Check if the specified paper
roll is used.
Use the correct paper roll.
(See “Paper Specifications”
in Chapter 1.)
The paper path may
be incorrect.
A Check if the paper supply path
is blocked.
Remove paper particles
and foreign substances.
The connector is not
inserted correctly.
A Make sure that the PF motor
cable pins are inserted in
connector CN6 of the main
circuit board.
Reinsert the connector.
The paper feed roller
may be bad.
B Check for wear and damage
on the surface of the roller.
Replace the paper feed
roller.
The paper hold roller
assembly may be
worn or damaged.
B Check for wear and damage
to the rollers of the paper hold
roller assembly.
Replace the paper hold
roller assembly.
Paper is not fed.
(Printing is
performed on
one line.)
(cont.)
Gears may be worn or
damaged.
B Check for wear and damage
to the paper feed reduction
gear and paper feed gear.
Replace any worn or
damaged parts.
Paper feed motor
assembly may be
bad.
B Check the continuity of the PF
motor cable assembly.
Replace the paper feed
motor cable assembly.
The paper feed motor
may be bad.
B The cause is none of the
above.
Replace the paper feed
motor.
Table 4-2 Troubleshooting table for bad printing (Continued)
Problem Probable cause Level Checkpoint Action