Shutter not working

If the shutterphotodiode is working properly, you can hear it click when it moves (much louder when it is being closed). If the shutter is not working, check to see that its computer input is hooked up to the DAC output channel 4. Then make sure that the DAC is getting the ``Port 4'' light to go on and off when you try to close and open the shutter. If the light does not respond to your activity, exit the program, turn off the DAC and back on, and try again.

On the other hand, the shutter can also get physically stuck. In this case, try operating it manually by flipping the switch on the shutter control obx (located between the inboard beamline ion gauge and pump controllers). Also, there is a disc on the actual shutter assembly that can be rotated; rotating it may get the shutter unstuck.