Troubleshooting LQ-300 Service Manual
5.2 UNIT LEVEL TROUBLESHOOTING
You may be able to identify the defective unit just from the symptom displayed. The table below
provides the symptoms for a number of failures, so that you can easily identify the problem. Once
the problem has been identified, refer to the flowchart listed in the right-hand column of the table
bel~w
to determin
e the cause of the problem.
Table 5-6. Symptoms and Problems
Symptom
Problem
See Page
Printer fails
to operate
● Carriage does not move.
when the power is on.
5-5
. Control panel indicator
LEDs do not light.
Abnormal carriage
●
Carriage moves away from
home position at power on.
operation.
. The carriage returns to home position correctly, but the
5-6
printer then fails to enter the READY mode.
Printing is faulty during
● No printing at all.
self-test, but carriage
. Faulty printing — some of the dot are not printing.
5-7
oDeration
is normal.
Abnormal paper feed.
. The printer prints but paper feeds incorrectly.
5-8
[
Abnormal control
panel operation.
Data sent by the host
computer is printed
incorrectly.
. When the LF/FF button is pressed, no paper is fed.
I
5-9
. Carriage operates normally at power up, and self-test
is executed
correotly,
but data is not printed.
5-1o
. Data from the computer is printed
inoorreotly.
The repair procedure flowcharts use the following symbols:
o
Decision
v
v
N
Return to the
Start of the item
END
Figure 5-3. Flowchart Symbols
5-4
Rev.A
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