DU-AG-0021-25 Rev C 1/09/07 GCX Corp. Page 4 of 7
Counterbalance Adjustment
The VHM Arm must be adjusted to counterbalance the mounted instrument throughout the Arm’s vertical range of motion.
When properly counterbalanced, the VHM Arm will maintain its height without engagement of the Height Locking Lever or
Locking Knob. Because instrument weights vary, adjustment will typically be required to achieve optimal performance. A
1/2" [13mm] socket wrench is provided for this critical adjustment.
To adjust counterbalance:
1. Grasp the Arm behind the mounted instrument(s) and carefully move the Arm to a horizontal position that allows
access to the Adjuster Cover (below left). Lock Arm in horizontal position.
2. Open the Adjuster Cover by inserting a flat blade screwdriver in the slot at the rear of the Cover and prying upward. If
necessary unlock and readjust the Arm until the Counterbalance Adjuster bolt is accessible through the Adjuster Cover
(below center). Lock Arm when Counterbalance Adjuster is accessible.
3. With the 1/2" [13mm] socket wrench on the Adjuster, carefully unlock the arm. Turn the Adjuster
counterclockwise
(CCW)
to increase counterbalance force, or
clockwise (CW)
to decrease counterbalance force. Counterbalance is
correctly adjusted when the mounted instrument can be moved up or down with minimal force and does not rise or fall
after releasing the Arm.
4. Close the Adjuster Cover.
WARNING: Do not attempt counterbalance adjustment unless the instrument and accessories are
mounted on the Arm. Use caution while performing this procedure.
Adjuster Cover
Counterbalance Adjuster Bolt
1/2'' [13 mm] Socket Wrench
CW
Decreases Force
CCW
Increases Force
