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Carrier Motor (PRTOS)
The carrier motor test checks the carrier motor phases
at low speed and then moves the head to the ramp, out
of the left margin, and back to the ramp at normal
speed.
The motor phases are tested by generating a series of
long pulses with a 50% duty cycle. These move the
motor slowly forward in equal steps. Failing motor
phases move the motor in steps that are not equal. The
motor might also move backward. It is normal for the
motor to step backward for the first step to locate
correct position.
The motor continues in slow speed until the start switch
is pressed or until the motor has advanced 256 steps.
For either action, the motor returns the head, at normal
operating speed, through the left margin to the ramp.
From the ramp, the head is moved out of left margin
and then back to the ramp. This movement (from ramp,
out of left margin, and back to ramp) continues until you
press the Stop switch.
The complete test can be repeated from the start by
pressing the Stop switch and then the Start switch.
The 'printer reset' line (A1A3B12 or B1A1B12) is
available as a probe point during this test.
Forms Motor (PRTOS)
This test checks the forms motor phases at slow speed
and then operates the motor at normal operating speed
to check forms feed and forms emitter operation.
The motor phases are tested by generating a series of
long pulses with a 50
%
duty cycle. These pulses move
the motor slowly (at part of a space per increment)
forward in equal steps. Failing motor phases move the
motor in steps that are not equal. The motor might also
move backward. It is normal for the motor to step
backward for the first step to locate correct position.
Too much platen or motor gear backlash (play) might
cause steps that are not equal (124, 125).
The low speed test continues until you press the Start
switch. Pressing the Start switch causes the forms
motor and emitter operation to be tested by running at
normal operating speed (high speed forms movement).
The forms motor operates smoothly at this speed in a
forward direction. The operation continues until you
press the Stop switch.
191
Wiring Diagram,
Diagnostic Aids
Note: Light 8 might turn on while you are running
PRT06. When the Stop switch is pressed while the test
is running, various lights will turn on depending on the
test status when the switch was pressed. The lights
should be ignored for MAP purposes.
The test can be repeated from the start at any time by
pressing the Stop Switch and then the Start switch.
The 'printer reset' line (A1A3B12 or B1A1 B12) is
available as a probe point during this test.
Alignment (PRT07)
The alignment test prints the alignment character across
a 132-character line and then prints the same character
while returning without a line space. The test continues
until you press the Stop switch. At the end of the print
line in which the Stop switch was pressed, the head is
returned to the left margin.
If the test is allowed to continue for 256 lines (5
minutes on 120 cps models) the test is ended and
cannot be restarted until the test is selected again.
The 'printer reset' line (A 1A3B12 or B1 A 1 B12) is
available as a probe point during this test.
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Maintenance
5256 MIM
1-75
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