Welch Allyn MicroTymp 3 portable tympanometric instrument - User Manual User Manual
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Maintenance and troubleshooting
Welch Allyn MicroTymp3 portable tympanometric instrument
A properly functioning instrument will produce two results:
•
A flat tympanogram (see the figure below). All data points must fall within the two
bottom rows of the graph.
•
An ear canal volume (Vea) which corresponds to the cavity tested. See the Expected
Vea readings table for the acceptable range for each cavity both at sea level and at
different altitudes.
If the readings do not fall within the acceptable range, then the Handle requires
calibration. Send the Handle to a Welch Allyn service location.
As the altitude above sea level increases, the admittance of an air-filled cavity also
increases. Therefore, at altitudes above sea level, results using the MicroTest Cavity will
change.
1000-Hz check
1.
Make sure the Handle is in 1000-Hz mode.
2.
Using any size probe tip, place the probe tip against the 0.5 cc cavity as if it were an
ear. Hold the handle and MicroTest Cavity carefully to prevent movement. Depress
the TEST button and test the cavity as you would an ear.
3.
Store the information using either the right or left memory buttons.
4.
Repeat Steps 2 and 3 using the 2.0 cc cavity. Store the information in the opposite
memory location used in Step 2.
The Handle should display REFER 0.4 or less in both the 0.5 cc and 2.0 cc cavities.
Expected Vea readings for MicroTest cavity
Cavity Measured
Acceptable
Tolerances
Acceptable Range
at Sea Level
Acceptable Range
at 3000 ft (914 m)
Acceptable Range
at 5000 ft (1524 m)
0.5 cc Cavity
±
0.1 cc
0.4 cc to 0.6 cc
0.4 cc to 0.6 cc
0.5 cc to 0.7 cc
2.0 cc Cavity
±
0.1 cc
1.9 cc to 2.1 cc
2.0 cc to 2.2 cc
2.0 cc to 2.2 cc
Refer to the Influence of altitude table on
for a more comprehensive treatment of altitude’s effect.
Tympanogram from 0.5 cc cavity
Note
While the MicroTest Cavity provides a functional test, it does not replace full
calibration. Welch Allyn recommends that the Handle be calibrated annually.