Casio UP-250 Technical Manual page 87

Table 4-1 Troubleshooting table for printer operation failure (continued)
Problem Probable cause
Semi-automatic The paper supply
loading is not operation may be
executed. incorrect.
(Paper is not
The paper path may
fed.)
be incorrect.
The connector is not
inserted correctly.
The paper feed
motor may be bad.
The paper hold
roller assembly may
be worn.
The gears may be
worn or damaged.
The paper detection
switch assembly
may be bad.
Table 4-2 Troubleshooting table for bad printing
Problem Probable cause
The printer does The ribbon in the
not print. (The ribbon cassette may
carriage motor be bad.
operates, but
The platen gap may
nothing is
be incorrect.
printed, or the
print color is
light.)
The common wire of
the print head unit
may be bad.
The head flexible
plastic cable (FPC)
may be bad.
Dots are missing The head FPC may
continuously. (A be bad.
specific dot is
The drive coil of the
not printed.)
print head unit may
be bad.
The dot wires of the
print head unit may
be bad.
Level Checkpoint
A
Check if the paper roll
meets printer specifications.
Check if the paper supply
A
path is blocked by paper
particles or foreign materials.
Make sure the PF motor cable
A
pins are inserted in connector
CN6 of the main circuit board.
Check if the motor rotates
B
during semi-automatic loading.
B
Check if the paper hold
rollers are worn or
damaged.
B Check if the paper feed
reduction gear and paper feed
gear are worn or damaged.
B Using an oscilloscope, check
if the detection signal is output
when roll paper is inserted.
Level Checkpoint
A Check if the color of the
ribbon is faded or the ribbon
is wrinkled or torn.
B Check the platen gap
(standard: 0.55 mm ± 0.05 mm).
B
Check the continuity of the
common wire.
Check the continuity of the
B
common line.
Check the continuity of the
B
head FPC.
B Using a meter, check the
resistance of the
corresponding drive coil.
(Standard: 19.2 ohms ± 5%)
Check if the dot wires are
B
broken.
— 78 —
Action
Use the correct paper roll.
(See "Paper Specifications"
in Chapter 1.)
Remove any pieces of
paper, paper particles, or
foreign materials.
Reinsert the connector.
Replace the paper feed
motor.
Replace the paper hold
roller assembly.
Replace any worn or
damaged parts.
Replace the paper
detection switch assembly.
Action
Replace the ribbon
cassette.
Adjust the platen gap.
(See "Adjustments" in
Chapter 5.)
Replace the print head
unit.
Replace the head FPC.
Replace the head FPC.
Replace the print head
unit.
Replace the print head
unit.