• Topic ID: id_16158073
  • Version: 2.0
  • Date: Jun 10, 2020 2:42:14 AM

Pancake DAS 16 General Cleaning

Prerequisites

Overview

The DAS air plenum and filters have accumulated dust. This can restrict airflow leading to ADB card over-temp errors and/or dust/dirt contamination of the chassis interior components.

Procedure

    Notice Image
    • notice
    • Failure in properly using the Aero Duster Spray System and ESD grounding generates a static charge of DAS components up to 12,000 volts.
  1. Accumulate cleaning materials.
  2. Take a DC Noise baseline scan using DASTOOLS Manual test.

    • This is to establish the DAS' current noise characteristics. Do not troubleshoot any noise failures until after the cleaning. The cleaning may “fix” some noise issues.

    • Since this procedure requires the removal and handling of the ADB boards, it may induce problems. The baseline scans will be repeated after cleaning to verify DAS performance, however it may be important to know if the cleaning caused problems or if the DAS had characteristic spikes, humps before the cleaning. This information will help determine if troubleshooting or further DAS integration is necessary.

  3. Turn Off DAS Power Supplies.
  4. Remove the Air Plenum.
  5. Remove Pancake DAS covers. Follow the procedure of Pancake DAS covers removal.
  6. Manually rotate the Gantry so that the DAS is at the 90 degree position.
  7. Remove all ADB cards from the backplanes in sequence.

    • Each board should be placed in an ESD bag or on an ESD mat.

    • The order of the boards must be noted so that when the boards are re-installed, they are in the same location as original. This way, only FastCal will need to be performed. If the boards are not in the same location, Full Air and Phantom Calibrations will be required, including DAS Gain and Collimator Cals.

    8. Notice Image
    • notice
    • When using Aero Duster and the Aero Duster Spray System, do not invert the can as this will cause liquid to come out. Testing has shown that this can cause a large static charge to develop where the spray hits.
  8. Cleaning the backplanes:

    Using the Aero Duster and spray system nozzle, blow from the inner diameter of the chassis. Blow air around the connectors, corners of chassis, and chassis holes. Visually inspect and manually remove any debris that is not blown out. The ionizing fan may also be used to eliminate built-up charges on the chassis.

    • Cleaning the ADB Boards:

      • Make sure you are fully grounded using your ESD strap.

      • Hold one board at time, and blow Aero Duster across the board, removing the dirt/dust that may have accumulated between component pins, etc.

      • After the board is cleaned, use the ionizing fan to remove any built-up charges on the board, then re-install the board in its original location. Failure to do this may cause phantom calibrations to be re-done.

      • Repeat steps until all chassis and boards are cleaned and installed.

      • Turn the DAS on and let it warm-up. It takes two minutes of warm-up time for every minute the DAS was turned off, up to one hour. The DAS can be warming up while the Air Plenum is being cleaned.

    • Cleaning the Air Plenum.

      • Blow or vacuum off the dirt/dust from the the Air Plenum, as well as from the cooling fan blades and fan guards. If you use water to rinse the filters after vacuuming, make sure the filters are completely dry before re-inserting them into the air plenum.

      • Re-install the Air Plenum.

    • Verify all covers are installed and complete the following tests within DAS Tools:

      • 1 iteration of DC Noise and DC Offsets.

      • 1 iteration of Pop Noise and Microphonics.

        All tests must pass. If not, troubleshoot and correct the failures.

Finalization

  1. Complete a Fastcal.
  2. Perform Image Quality testing.