Repair By Unit Replacement - Epson LQ-1070 Service Manual

REV.-B

5.2 REPAIR BY UNIT REPLACEMENT

For most problems, it is sufficient for you to determine the difficulty to the unit level. Refer to Table
5-3, identify what the problem is, then perform the checks according to the corresponding flowchart.
Symptom
Printer fails to operate
power is on.
Carriage operation is abnor-
real.
Printing is faulty during self-
test, but carriage operation is
normal.
Paper feeding is abnormal.
Control panel operation is
abnormal.
Printing of data sent by the
host computer is faulty.
The repair procedure flowcharts are represented using the following symbols:
Table 5-3. Svm~toms and Reference Pages
when
Carriage does not move.
. Carriage moves away from home position at power
on.
The carriage returns to the home position correctly,
but the printer then fails to enter the READY mode.
No printing at all.
.
. Faulty printing - some of the dots are not printed.
. No paper is fed.
Regular paper feed, but with variations in the separa-
tions between lines.
When the LF switch is activated, no paper is fed.
Carriage operates normally at power on, and self-test
is executed correctly.
Print data from the computer, however, is not printed
correctly.
Start
Processing
Forwarding to another
item
Decision
Problem
Branching
Returning to the Start of the item
End
5-2
See Page
5-3
5-4
5-5
5-9
5-12
5-13