Casella CEL CEL-63X - Manual (Page 30)

CEL-63x Environmental & Occupational Noise Meter
30 Casella CEL
If the calibration fails, this indicates a technical problem with either the
instrument or the calibrator. The basic checks to try if the calibration fails are
as follows:
Check that the microphone and calibrator are fitted correctly.
Inspect the microphone and the calibrator‟s cavity for signs of damage.
Check that the calibration level is set correctly.
If the instrument persists in failing calibration, contact Casella CEL for advice.
Press Exit to exit the Calibration mode without saving the new calibration.