Max/Min Recording; Auto-Power Off; Calibration; Battery Replacement - Extech Instruments 407730 User Manual

MAX/MIN Recording

In this mode the meter records the Maximum and Minimum readings and stores them into
memory.
1. Press the REC button to enter the RECORD mode. The "REC" icon will appear in the
display.
2. Press the REC button again to display the minimum value recorded since the mode was
entered. The "MIN" icon will appear in the display. The meter is not recording during this
time.
3. Press the REC button again to display the maximum value recorded since the mode
was entered. The "MAX" icon will appear in the display. The meter is not recording
during this time.
4. Press the REC button again to display the present dB level and continue recording.
5. Press and hold the REC button until the "REC" icon clears to exit the mode.

Auto-Power Off

The meter will automatically shut off after 20 minutes of operation. To disable this feature:
1. With the meter OFF, Press the
2. will appear in the display
3. Release the button and then release the MAX HOLD button.
4. The meter will remain on until the power button is pressed.

Calibration

To calibrate the meter, an external calibrator such as the Extech 407744 or the Extech
407766 is required in addition to a small screw-driver.
1. Turn the meter ON
2. Select the 80 to 110dB range
3. Select 'A' weighting and 'SLOW' response
4. Place the microphone into the calibrator. Set the calibrator to output a 1kHz sine wave
@ 94dB
5. Adjust the calibration potentiometer for a display as close as possible to the calibrator's
output

Battery Replacement

When the low battery icon appear replace the battery by removing the screw securing
the rear battery compartment and replacing the 4 AAA batteries.

Tripod Mount

A camera tripod mount is located on the rear of the meter for increased stability and
elimination of body reflections.

Measurement Considerations

1. Wind blowing across the microphone increases the noise measurement. Use the
supplied windscreen to cover the microphone when applicable.
2. Calibrate the instrument before each use if possible. Especially if the meter has not
been used for a long period of time.
3. Do not store or operate the instrument in areas of high temperature or humidity.
4. Keep meter and microphone dry.
5. Avoid severe vibration.
6. Remove the battery when the meter is to be stored for long periods of time.
and MAX HOLD buttons simultaneously.
4 Model 407730 Version 1.3 June 2004