1998-08-0314 MAC 500
section 3
ADJUSTMENT
3.1 I
NDEXING
METHODS
Effects indexing in the MAC 500 is determined by one of three methods. The adjustment procedure for the effect depends on its
indexing method. The lamp must be properly adjusted before the alignment of the other effects can be adequately judged. Refer
to procedure 3.11.
3.1.1 M
ECHANICAL
INDEXING
The effect is driven against a mechanical stop and comes to rest at a step position. The
adjustment is performed from this step position and thus requires that the motor is
under power. Please review the safety information in section 1 before proceeding.
The general adjustment procedure is as follows.
1. Apply power and reset the fixture. The motor must be under power while
performing the adjustment.
2. Loosen the set screws. Set the wheel (or arm) to the specified distance
from the motor or other reference point, or as required for free rotation. Tip:
Drill bits make excellent spacers.
3. Tighten the set screws just enough to fix the wheel’s position along the
motor shaft. The wheel must be able to turn on the shaft without moving the
motor.
4. The motor must be where it stopped after resetting. Move the wheel so that
the angle between it and the mechanical stop is 1/3 of a motor step. Motors
in the MAC 500 have 50 whole steps (cycles); each step is 7.2° and the
angle between the effect and the stop is 2.4°. The distance (A) between the
wheel and the stop may be calculated as follows:
A = B (tan 2.4°)
where B is the distance from the motor shaft to the point of contact.
5. Tighten the set screws. Run the effect through its positions and then recheck the distance.
3.1.2 E
LECTRIC
INDEXING
The MAC 500’s pan and tilt are indexed using electric switches. No adjustment is necessary as long as the switches close dur-
ing the reset procedure.
3.1.3 M
AGNETIC
I
NDEXING
The MAC 500’s rotating gobos, fixed-gobo wheel, and 2 color wheels are indexed magnetically. A Hall sensor IC detects a
miniature magnet mounted on the effect wheel. Proper adjustment is critical. If the wheel or sensor is out of position, the effect
may not reset, or, if it resets, may begin to "wander" when the fixture reaches operating temperature. This is due to the fact that
sensors' detection range is small and they only "look" for the magnet when the motor is at a cycle position, i.e., every 7.2
degrees.
Note: The IC sensor must be parallel with the magnet for maximum sensitivity.
Adjustment is performed from a step position and thus requires that the motor is under power. Please review the safety informa-
tion in section 1 before proceeding.
The adjustment procedure is as follows.
1. Apply power and reset the fixture but do not strike the lamp. The motor must be under power while performing
the adjustment.
2. If the wheel fails to reset, wait for it to time-out and adjust from this position.
3. Loosen the set screws. Set the wheel to the specified distance from the motor or other reference point, or as
required for free rotation.
4. Tighten the set screws just enough to fix the wheel’s position along the motor shaft. The wheel must be able to
turn without moving the motor.
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