Identify Problems From Symptoms - Epson LQ-300 + Service Manual

EPSON LQ-300+

3.2.3 Identify Problems From Symptoms

This section contains procedures to identify problems from abnormal symptoms.
Repair/replacement is usually performed as a unit, however, parts level replacement
can be performed if neccasary.
Find your symptom referring to the table below and go to the corresponding table.
Table 3-2. Symptoms and Solutions
Symptom
Control panel LED does not operate at
When power is applied,
all.
the printer does not
Printer mechanism does not operate at
operate.
all.
• Control panel indicates fatal error.
When power is applied,
the printer becomes fatal • The printer indicates error after
error. initialization.
• Platen gap is not correct.
• Printhead and ribbon mask is
Self-test print is
abnormal or their life are over.
abnormal.
• Vertical direction printing quality is
abnormal.
• Paper feed operation is not
performed.
• Paper switching is abnormal.
Paper feed is abnormal.
• Line feed is not equal.
• Skew is generated.
• LED indication is abnormal.
Control panel and
switches do not operate • Cannot input from switches.
properly.
• Self-test is normal, but the printing
Printing operation is
from host computer is abnormal.
abnormal when it is on-
line.
Troubleshooting
Problems Check Table
Table 3- 3 on page 47
Table 3- 4 on page 47
Table 3- 5 on page 48
Table 3- 6 on page 48
Table 3- 7 on page 48
Table 3- 8 on page 48
Table 3- 9 on page 49
Table 3-3. Control Panel LED Does Not Light On.
Cause
Blowout of a fuse on Is a fuse on the power
the power board. board blew out?
Are connectors
Connector is not
connected to the
connected to the
power board
power board.
properly?
Power switch is Is conductivity of the
defective. switch is OK?
Are +5VDC and
Power board is
+35VDC OK when
defective.
the power is on?
Power board and the
Is CN8 connected
main board are not
properly?
connected properly.
Main board is
defective.
Control panel harness Is the harness of the
is not connected control panel
properly. connected properly?
Control panel board
or harness is
defective.
Table 3-4. Printer Mechanism Does Not Operate.
Cause
Any of CN3 to CN12
Are all connectors
is not connected to the
connected properly?
main board properly.
Main board is
defective.
Printer mechanism is
defective.
Troubleshooting
Check Point Y/N
Check the electric circuit and
YES printer mechanism. If there is no
short circuit, replace the fuse.
NO Replace the power board.
YES Replace the power board.
NO Replace the power board.
NO Connect CN8 properly.
- - Replace the main board.
NO Connect the harness properly.
- - Replace the control panel.
Check Point Y/N
NO Connect them properly.
- - Replace the main board.
- - Replace the printer mechanism.
Revision C
Solution
Solution
47