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Section II
Before applying power to the plotter,
check the line voltage selection (visible
through the small window in the rear
panel) and make sure the selected line
voltage and fuse value are correct. If
not, refer to Line Voltage and Fuse
Selection in Section I.
b. Apply power to the plotter.
c.
With the PAPER LOAD lever in the LOAD posi-
tion, place a sheet of paper (ISO A4/ 8-112
X 11
in. or ISO
Aa/
11 X
17 in.) against the left-hand
rail and the rear guide. Lower the lever to the
PAPER HOW position and be sure that the
plotter is set for the proper paper size.
d.
Select a pen by pressing one of the six pen push-
buttons and then operate each of the front-panel
controls. Vertical, horizontal, and diagonal lines
(using the directional controls with a pen down)
should be smooth.
NOTE
If the pen is down, it will lift when
either Pl or P2 is pressed. The VIEW
pushbutton is a latching control. After
VIEW
is
pressed once, the other controls
will not operate until VIEW is pressed
a second time. The ERROR light should
be on when in the VIEW mode. The
ERROR light should be on when the
PAPER lever is in the LOAD position.
If Pl or P2 is pressed while the lever
is in LOAD, the ERROR light should
flash. This error may be cleared by
moving the lever to HOLD and back
to LOAD, or by pressing ENTER and
VIEW at the same time, in which case
the plotter initializes again. While the
plotter is ON, and the PAPER lever is
in the HOLD position, the ERROR
light flashes very briefly approximately
every five seconds when the motor
power supply voltage
is
sensed.
2-15. HEWLETT-PACKARD GRAPHICS
LANGUAGE
2-16.
The Model 7475A recognizes the Hewlett-Packard
Graphic Language (HP-GL) instructions listed in Table
2-2.
2-2
Model 7475A
2-17. DEMONSTRATION PLOT
2-18.
The Model 7475A contains a demonstration plot
stored in Read Only Memory (ROM). The running of
this plot
will
verify proper operation of most of the logic
circuits as well as the operation of the paper and pen
drive mechanisms; however, it does not test the 1/0
circuitry.
To
run
the demonstration plot proceed as follows:
a.
Make sure six pens are installed in carousel.
b. With the PAPER LOAD lever in the LOAD posi-
tion, place a sheet of paper (A4/ 8-1/2
X 11
in. only)
against the left hand rail and the rear guide.
Lower the lever to the paper HOW position.
c.
While holding down buttons Pl and P2, apply
power to the plotter. See Figure 2-1. Release buttons
after initialization starts.
d. The resultant plot is illustrated in
Figure
2-2.
2-19. TEST PROGRAM
2-20.
The program in Figure 2-3 is written in BASIC
language specifically for the HP Model 85 Personal
Computer, but may be adapted to other controllers. This
program tests the input/output circuits of the 7475A and
the majority of the logic circuits, as well as the operation
of the paper and pen drive mechanisms. The resultant
plot is illustrated in Figure 2-4.
NOTE
Lines beginning with an exclamation
point are only explanatory and not part
of the plot program. Those lines may be
omitted when entering the program.
The addresses shown in lines 130, and
140 are only examples, and may vary
with the system or computer used.
2-21. REPEATABILITY
2-22.
To verify repeatability specification (Table 1-1)
load six new pens in the carousel and run the test
program previously described. Using an optical com-
parator, verify that the repeatability points on the test
plot are within 0.1
mm
using the same pen, and within
0.2 mm using a different pen. See Figure 2-5.
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Table of Contents
Troubleshooting
