Tektronix 4010 Maintenance Manual page 59

c. Put the vertical thumbwheel to its upper limit.
d. Enter PAGE and CTRL SHIFT K and CTRL Z to
erase the display and regain the crosshair. (CTRL SHIFT K
and CTRL Z must be entered to regain the crosshair cursor
each time the display is erased, since PAGE also resets the
Terminal to Alpha Mode.)
e. Check display positioning. It should meet the
following requirements (see Fig. 4-8):
Horizontal line
Vertical Line
Should remain in view
Both ends occur before reaching
edges of display area
Approximately centered hori-
zontally in display area
Approximately 18.75 cm (7.4
inches) long
Parallel with top edge of display
area
Deviation from mean straight line is
within approximately 2.8 mm (0.11
inch)
Bottom end occurs approximately
1.27 cm (0.5 inch) before reaching
edge of display area.
Horizontal intercept is approxi-
mately 14 cm (5.5 inches) above
bottom of vertical line
Approximately parallel with left
edge of display area
When positioned near left edge of
display area (by using horizontal
thumbwheel), deviation from mean
straight line is within approxi-
mately 2.1 mm (.08 inch)
f. If lines are excessively long, set X GAl Nand/or Y
GAIN (top-left in pedestal) fully counterclockwise.
g. Adjust display positioning as follows; adjustments are
located near the top-left in the pedestal unless otherwise
stated:
®
(1) Adjust X POS for approximate left-right
centering of horizontal line.
Adjustment-4010 Maintenance
(2) Adjust Y POS to approximately center the
vertical line segment described by its lower end and the
point of intercept with the horizontal line (vertical
thumbwheel at upper limit). See Fig. 4-8.
(3). If necessary, rotate the yoke housing or yoke-
mounting bracket (depending on type of assembly to ob-
tain approximate parallelism between the ends of the
horizontal line and the top edge of the display area. Two
nuts hold the yoke housing in place behind the center
divider in the display unit (Fig. 4-6). Final adjustment
and tightening of the yoke housing is done in a later
step.
(4) Adjust X GEOM for approximate straightness of
the vertical line; vertical line to be positioned as close to
the left edge of the display area as possible by using the
horizontal thumbwheel.
(5) Adjust Y GEOM for approximate straightness of
horizontal line, with vertical thumbwheel at its upper
limit.
(6) Adjust X GAIN for 18.75 cm (7.4 inches) hori-
zontal line length.
(7) Readjust X POS for horizontal line centering as
necessary.
(8) Press PAGE and then enter four Zs. The Zs
shoUld store. If storing doesn't occur, increase the OP
LEVEL setting while entering Zs until they store. Then
press PAGE and again enter four Zs.
,..-_ _ _ _ _ _ Equal Spacing - - - - - -.....
14----"'18.75cm(7.4inch)
--------t
Fig. 4-8. Display Positioning, Using Cross-hair Cursor.
4-13