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94MS41 Rev C1 S/W Ver. 2.06
Remove the 6 screws from each side of the lamphead and remove the
two endcaps. On LT8 lampheads you can now access the trigger board
and shutter position switch that are located at the opposite end from the
shutter motor under the air plenum plate.
Shutter
The shutter is controlled by the PC board, with information from a switch
in the lamp head to provide position information. During cool-down and
exposure, the shutter is open and during warm-up and idle, the shutter is
closed.
The PC board compares the shutter position with the requested position.
The shutter motor will run until the switch position matches. The shutter
motor has a brake that is magnetically operated. Whenever the power is
released from the motor, the brake falls into a slot. There is an LED on
the PC board that lights whenever the shutter is being energized. (Look
in the PC board pin section for a diagram of the LEDs).
Shutter Switch
The switch provides shutter position information to the PC board. This
switch is in the lamp end where the cable enters, inside the manifold
cover. The cam is in the chamber with the shutter. A failure of the switch
can cause the shutter to rotate continuously or erratically. Similar
problems may be due to the shutter motor brake, the idle setting, or the
PC board.
The switch contacts close when the shutter is fully open and remain closed
until the shutter closes. This level can be measured on the terminal strip
from terminal 9 (+) to terminal 7 (-). The level is 12 VDC when the
shutter is closed, and 0 V when the shutter opens. The switch is in the
lamp head on the end where the cable enters inside the air manifold on
older units. On newer units we use the normally open contacts, COM
contact and the center contact. We use the normally closed contacts, the
two outside leads, not the center contact. This switch is adjustable on
older units. We recommend scribing a line around the switch and the
bracket, if replacement is necessary, to return to the same position. The
switch roller should be centered on the cam and closed when the cam
pushes the wheel on the switch halfway.
Side
View
13-9
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