Read Sharp UP-600 / UP-700 (serv.man21) Service Manual online
3. Repair Guidelines
Phenomenon
Condition
Cause
Level
Checkpoints and
Checking Method
Repair Method
1. Printing is
not executed.
Nothing is
printed.
printed.
(1) The Head cable is
disconnected.
A
•
Verify that the Head cable
is properly connected.
is properly connected.
•
If the FFC-head is not
properly connected,
connect it firmly.
properly connected,
connect it firmly.
(2) The common or signal line of
the Head cable is broken.
B
•
Check the common and
signal lines of the Head
cable for continuity.
signal lines of the Head
cable for continuity.
•
If continuity cannot be
confirmed, replace the
Head cable.
confirmed, replace the
Head cable.
(3) The printhead does not
contact the platens.
A
•
Verify that the head up lever
is set to the proper position.
is set to the proper position.
•
Set the head up lever to the
printing position.
printing position.
(4) The input pulse is defective
B
•
Verify with the oscilloscope
that the input pulse is
within the specified range.
that the input pulse is
within the specified range.
•
If the input pulse is not
generated or is not within
the specified range, adjust
the drive control circuit.
generated or is not within
the specified range, adjust
the drive control circuit.
2. Dots are
missing
continuously.
continuously.
A specific dot is
not printed.
not printed.
(1) A foreign substance is
attached to the heating
elements of the printhead.
elements of the printhead.
A
•
Verify that nothing is
attached to the heating
elements of the printhead.
attached to the heating
elements of the printhead.
•
Clean the heating elements
of the printhead.
of the printhead.
(2) The heating elements of the
printhead are damaged.
B
•
Verify that the heating
elements of the printhead
are not damaged.
elements of the printhead
are not damaged.
•
If the heating elements are
damaged, replace the
thermal head.
damaged, replace the
thermal head.
(3) The signal line of the Head
cable is broken.
B
•
See Cause (2) of Phenomemon 1.
(4) The input pulse is defective.
A
•
See Cause (4) of Phenomenon 1.
3. Dots are
missing
occasionally.
occasionally.
Dots are
missing
occasionally or
the color of
some dots
becomes light.
missing
occasionally or
the color of
some dots
becomes light.
(1) A foreign substance is
attached to the surface of
each platen roller.
each platen roller.
A
•
Verify that nothing is
attached to the surface of
each platen roller.
attached to the surface of
each platen roller.
•
Clean the surface of each
platen roller.
platen roller.
(2) The surface of each platen
roller is deformed.
A
•
Verify that the surface of
each platen roller is not
deformed.
each platen roller is not
deformed.
•
If deformation is found,
replace the corresponding
platen roller ass’y.
replace the corresponding
platen roller ass’y.
(3) A foreign substance is
attached to the heating
elements of the printhead.
elements of the printhead.
A
•
See Cause (1) of Phenomenon 2.
(4) The heating elements of the
printhead are damaged.
B
•
See Cause (2) of Phenomenon 2.
4. The printing
color is light.
The overall
printing color is
light.
printing color is
light.
(1) The head up lever position is
not correct.
A
•
Verify that the head up lever is set to the correct position.
(2) Displaced or deformed
H-springs.
A
•
Make sure the H-springs are correctly installed and not
deformed.
deformed.
(3) The H/C frame is warped.
B
•
Verify that the H/C frame is not warped.
(4) The surface of the platen is
deformed.
A
•
See Cause (2) of Phenomenon 3.
(5) The heating elements of the
printhead have deteriorated.
B
•
Verify that the heating elements of the printhead have not
deteriorated.
deteriorated.
(6) The input pulse is defective.
A
•
See Cause (4) of Phenomenon 1.
(7) The roll paper is of poor
quality.
A
•
Verify that the specified-roll paper is being used.
•
Check the paper for proper color development and
excessive dust.
excessive dust.
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