AERI Scene Mirror Replacement Procedure

Tools and Equipment Required

  • Replacement mirror (Laser Beam Products p/n SNICU100-12-00)
  • Large phillips screwdriver
  • Ball driver set
  • Soft wipes
  • (Optional) Holding fixture for the scene mirror assembly
  • (Optional) Tweezers for holding mirror screws

Precaution

  • The motor cables must NEVER be disconnected with the motor controller powered, as it can damage the stepper motor.  Always power off the motor controller or instrument first.
  • Be careful if handling the drum around the scene mirror: it is thin and easily bent.
  • Do not touch the mirror surface. Wear gloves or use soft wipes when handling optics.
  • There are four springs that will come loose when the mirror is removed: be sure to collect them.
  • There may be thermal grease used between the back of the mirror and the heater plate: avoid contaminating any other surfaces with thermal grease.
  • The mirror assembly must be registered upward upon replacement for proper optical alignment.

Procedure

  1. Stop data collection and power off the instrument:
    1. Press ctrl-c up to 3 times in the black Cygwin window to terminate ingest.
    2. Switch off the power bar in the AERI back-end
  1. Remove the front panel from the AERI front-end.
  2. Remove the scene mirror/motor assembly from the front end structure:
    1. The interior fan may obstruct removal of the assembly.  In this case the fan assembly can be slightly rotated by removing the 3 front screws holding it to the hex.  Alternatively the entire fan assembly can be removed.
    2. Disconnect the 4 cables going to the trapezoidal plate (ensure that motor controller is powered off):
      1. ENCODER
      2. MOTOR
      3. MO TEMP / PE TEMP
      4. S MIRROR
    3. Unscrew the 4 screws on the trapezoidal plate (see Fig. 1).
    4. Pull the assembly carefully straight out of the support structure (see Fig. 2).
    5. Place the assembly carefully onto a flat surface, or place it onto a holding fixture (see Fig. 3).
  1. Inspect the area inside the hex (from where the mirror assembly was removed); note and clean any debris or obstructions (grass, dirt, nests, etc.).  Inspect the mirror drum for obstructions and circularity.  Note the condition of the mirror surface before replacement.
  1. Remove the old mirror:
    1. Remove the 4 screws and 8 washers that retain the mirror (see Fig. 4). A 7/64” ball driver is required as the driver will be slightly tilted when it is being used through the drum aperture. Note: avoid having the screws drop across the mirror surface and possibly scratch it.
    2. Carefully remove the mirror (see Fig. 5). The drum can be rotated so that the mirror drops out. Note: Wear gloves or use soft wipes when handling optics. Note: There are four springs providing pressure behind the mirror that will be loose when the mirror is removed: be sure to collect them (see Fig. 6).
    3. Remove the heater plate from the back of the mirror. There may be thermal grease holding this plate to the back of the mirror. Note: Avoid contaminating any other surfaces, especially the front of the mirror, with thermal grease.
    4. Carefully package the old mirror by avoiding contact/pressure on the front optical surface. Notify UW-SSEC and return the mirror to SGP for refurbishment.
  1. Install the new mirror:
    1. Ensure that the heating plate and the 4 springs are in proper position (see Fig. 6).
    2. Install the new mirror into position (see Fig. 5). Note: Wear gloves or use soft wipes when handling optics.
    3. Reinstall the 4 screws and 8 washers that retain the mirror (see Fig. 4). Only the nylon washers should be in contact with the mirror surface. Note: Avoid touching or scratching the mirror with the screws.
  1. Reinstall the mirror/motor assembly:
    1. Carefully insert the assembly straight into the support structure (see Fig. 2).
    2. Register the front plate upward when tightening the four socket head screws.
    3. Reconnect the 4 cables going to the trapezoidal plate.
    4. Return the interior fan assembly to it’s original position, if it was moved.
  1. Rotate the mirror/drum assembly by hand through its full range (250°) and check for any interference of the drum with the two baffles on the structure. (Removing the bottom plate hole cover allows access for hand rotation. Replace cover when done.)
  1. Reinstall the front panel onto the AERI front-end.
  1. Power on the instrument and resume data collection:
    1. Switch on the power bar in the AERI back-end
    2. Click ingest.bat on the desktop to begin ingest.

Figure 1: Unscrewing the mirror:motor assembly

Figure 1. Unscrewing the mirror/motor assembly

Figure 2: Mirror motor assembly removal or insertion

Figure 2. Mirror motor assembly removal or insertion

Figure 3: Removed mirror:motor assembly on holding fixture

Figure 3. Removed mirror/motor assembly on holding fixture

mirror_screws

Figure 4. Four sets of screws and washers retain the mirror

mirror_removal

Figure 5. Mirror removal/installation

mirror_springs

Figure 6. Four springs retaining the mirror