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Bulb Voltage
The ST9 series is equipped with a voltage compen-
sation device that will deliver the necessary bulb
output with a voltage range of between 110VAC
and 120VAC. Routine bulb voltage adjustments
are not necessary if supply voltage falls within this
range.
ADJUSTMENT
NUT
ADJUSTMENT
HOLE
LOWER
SUPPORT ARM
UPPER
RADIAL ARM
D. Lighthead Horizontal Rotation
Adjustment
The lighthead should maintain its position without
drifting, yet move freely. Normally this adjustment
is correct from the factory and does not change. If
the lighthead drifts, the most probable cause is a
non-plumb mounting hub.
Recheck the fixture mounting hub to make sure
that it is plumb. In most cases this will solve any
drifting problems. If not, use the following adjust-
ment procedure to adjust the bearing preload. See
figure 3-5.
Figure 3-5. Horizontal Rotation Adjustment
1. Locate the adjustment hole and rotate the
lower support arm until a set screw is visible in the
adjustment nut. Loosen the set screw with an allen
wrench.
2. Leave the allen wrench firmly seated in the
set screw; this will hold the adjustment nut captive.
Carefully rotate the lower support arm slightly.
Move the arm counterclockwise (viewed from the
bottom) to decrease tension and clockwise to
increase the tension.
3. Tighten the set screw, remove the allen
wrench and recheck the tension adjustment.
