Adjustments; Backlash Adjustment; Checking And Setting Backlash - American Dynamics AD1273 CobraDome Installation And Operation Instructions Manual

ADJUSTMENTS

ADJUSTMENTS

Backlash Adjustment

Proper backlash adjustment eliminates any apparent video
image hesitation during a slow pan rotation through 360
degrees. Also, when the pan action stops, the video image
should not bounce back and forth.

Checking and Setting Backlash

1) Disconnect all power to the CobraDome.
2) Remove the CobraDome chassis from the back box and
place the chassis on a solid, flat surface.
3) Obtain a #73 twist drill bit. Verify with calipers that the
solid end of the bit measures 0.023 inches (0.71mm)
NOTE: The thickness of a standard resistor lead is
approximately 0.023 inches/23 Mils (0.71mm) and
may be substituted for a #73 twist drill bit.
4) Insert the bit between any pan axis drive gear tooth and a
pan axis motor gear tooth (see Figure 23).
5) Slowly rotate the pan gear by hand and note the clearance of
the bit between the pan axis gear teeth and the pan motor
gear teeth.
Pan Axis
Drive Gear
Figure 22 - Pan Axis Drive Gear
6) Repeat the measurement process four times, using a
different location (typically between the gear spokes) on the
pan axis drive gear.
NOTE: During the cooling process, gears tend to warp
slightly and develop a "high" point. This high point
is generally found above the blank spaces between the
gear spokes (see Figure 22).
The backlash is properly adjusted when the bit fits snugly
between the "high" point on the pan motor drive gear teeth and
the pan gear teeth.
7) Adjust the backlash by loosening the pan axis drive motor
mounting bracket screws on the side of the CobraDome
chassis. Adjust the pan axis motor until the proper
clearance is achieved.
NOTE: The pan drive motor gear must always remain at right
angles to the pan axis drive gear.
Typical Location
of "High" Spot on Gear
Gear
Spokes
28
AD1273