Epson U375 - TM B/W Dot-matrix Printer, Техническое руководство

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4-13
Table 4-3. Printer Mechanism Problems (continued)
Level
B
B
A
B
B
Problem
Different character than
input code is printed.
(continued)
Ribbon feed mecha-
nism does not operate
and ribbon is not fed.
Slip paper eject waiting
status is not released
when slip paper is re-
moved.
Probable Cause
Command problem
Ribbon drive plate as-
sembly failure
Ribbon cassette life end
or failure
Gear wear, damage, or
contamination
Ribbon cassette and Rib-
bon take-up shaft as-
sembly fail to engage
circuit failure
Checkpoint
Check data sent from host with
hexadecimal dumping func-
tion.
Check to see if Ribbon drive
p l a t e a s s e m b l y m o v e s
smoothly.
Check to see if the ribbon is
rumpled or torn. Check ribbon
feeding by turning the ribbon
tightening knob.
Check each gear for wear,
damage, and contamination.
Check to see if ribbon cassette
is mounted correctly.
Action
Correct the application
program.
Replace Ribbon drive
plate assembly.
Replace ribbon cassette.
Remove any foreign mat-
ter or replace any dam-
aged gears.
Mount ribbon cassette cor-
rectly. (See Section 3.1.6,
Mounting and removing
the ribbon cassette.)
4.2 MAJOR PART
REPLACEMENT
4.2.1 Fuse Replacement
Follow the steps below to replace a blown fuse:
(1) Turn the printer off.
(2) Disconnect the external power supply.
(3) Disassemble the printer following the procedure de-
scribed in Section 5.2.1, Fuse replacement.
(4) Replace the blown fuse (125 V, 2.5 AT).
(5) Perform steps (1) through (3) in reverse.
If the printer still does not operate properly, or if the fuse
blows again, use the flowchart in Section 4.1.2 to check for
other problems.
4.2.2 Print Head Unit Replacement
Follow the steps below to replace the print head unit:
(1) Turn the printer off.
(2) Disconnect the external power supply.
(3) Disassemble the printer following the procedure de-
scribed in Section 5.2.2, Print head unit replacement.
(4) Replace the print head unit.
(5) Perform the gap adjustment described in
Adjustment
C in Section 5.3.4.
(6) Perform steps (1) through (3) in reverse.
4.2.3 J Guide Assembly B (Cutter Blade)
Replacement
Follow the steps below to replace the cutter blade:
(1) Turn the printer off.
(2) Disconnect the external power supply.
(3) Disassemble the printer following the procedure de-
scribed in Section 5.2.3,
J guide assembly B replace-
ment.
(4) Replace the J guide assembly B.
(5) Perform steps (1) through (3) in reverse.
CONFIDENTIAL