• Topic ID: BJ_201019_N01
  • Version: 2.0
  • Date: Nov 27, 2020 2:08:32 AM

HHS Scans

Prerequisites

The objective of this procedure is to validate HHS scans fit within specifications:

  • Attach oscilloscope to Inverter

  • Set up oscilloscope

  • Take each scan and record measurements

1 Data Acquisition

Procedure

  1. Move table to longitudinal home position.
  2. Select DIAGNOSTICS from Service Desktop.
  3. Select KV & MA (X-RAY).
  4. In kV and mA Test (X-ray Functional Test) pane, set following parameter values.
  5. In Gantry Params pane, set following parameter values.
  6. Click RUN.
  7. Press START on the GSCB when it flashes.
  8. Verify that the following conditions are met:
    1. The kV and mA X-ray tool “Cathode/Total kV Average Value” is within limits defined in Scan Protocol Parameters and Limits for prescribed scan protocol.
    2. The kV and mA X-ray tool “mA Average Value” is within limits defined in Scan Protocol Parameters and Limits for prescribed scan protocol.
    3. The kV and mA X-ray tool “mA @ 5 msec Average Value” is within limits defined in Scan Protocol Parameters and Limits for prescribed scan protocol.
    4. The kV and mA X-ray tool “Exposure Duration Average Value” is within limits defined in Scan Protocol Parameters and Limits for prescribed scan protocol.
      note:

      If any of these conditions are not met, perform appropriate corrective action and retest.

  9. Record results in appropriate GE e4879 Installation form, GE e4879 Certified Component Verification form, or GE Data Report Planned Maintenance Schedule form.
  10. Repeat Step 4 through Step 9 for all protocols defined in Scan Protocol Parameters and Limits.
  11. Click DISMISS in kV and mA Test window.
  12. For failed results, isolate root cause by running the following procedures in order shown below and perform appropriate corrective action.
    1. Meter Verification (Pro, RT, VCT)
    2. HV Tank Feedback Resistor Verification (Pro, RT, VCT)
    3. Filament Calibration
  13. Store data form with system history records.

2 Scan Protocol Parameters and Limits

Procedure

  1. Focal spot protocol parameters and limits as below shown.

3 Finalization

Procedure

  1. Ensure all measurements are within the specified limits. If any one scan is out of specification limits, take the appropriate service action.