Care And Maintenance; General Maintenance Procedures - Interacoustics AD226 Instructions For Use Manual

AD226 Instruction for Use - US

4 Care and Maintenance

4.1 General Maintenance Procedures

The performance and reliability of the AD226 will be prolonged if the following recommendations for care
and maintenance are adhered to:
Great care when handling the headset:
Great care should be considered when handling the headset as dropping it may alter the calibration.
Annual Calibration:
It is recommended that routine check procedures are carried out weekly in full on all equipment in use.
Check 1-9 outlined below should be followed on the equipment on each day of use.
The purpose of routine checking is to ensure that the equipment is working properly, that its calibration
has not noticeably changed, and that its transducers and connections are free from any defect that might
adversely affect the test result. The checking procedures should be carried out with the audiometer set up
in its usual working situation. The most important elements in daily performance checks are the subjective
tests and these tests can only be successfully carried out by an operator with unimpaired and preferably
known good hearing. If a booth or separate test room is used, the equipment should be checked as
installed; an assistant may be required in order to carry out the procedures. The checks will then cover
the inter-connections between the audiometer and the equipment in the booth, and all connecting leads,
plugs, and socket connections at the junction box (sound room wall) should be examined as potential
sources of intermittency or incorrect connection. The ambient noise conditions during the tests should not
be substantially worse than those encountered when the equipment is in use.
1. Clean and examine the audiometer and all accessories.
2. Check earphone cushions, plugs, main leads and accessory leads for signs of wear or damage.
Damaged or badly worn parts should be replaced.
3. Switch on equipment and leave for the recommended warm-up time. Carry out any set-up
adjustments as specified. On battery-powered equipment, check battery state using the
manufacturer's specified method. Switch on equipment and leave for the recommended warm-up
time. If no warm-up period is quoted, allow 5 min for circuits to stabilize. Carry out any setting-up
adjustments as specified. On battery-powered equipment, check battery state.
4. Check that earphone and bone vibrator serial numbers are correct for use with the audiometer.
5. Check that audiometer output is approximately correct on both air and bone conduction by
conducting a simplified audiogram on a known test subject with known hearing; check for any
change.
6. Check at high level (for example hearing levels of 60 dB on air conduction and 40 dB on bone
conduction) on all appropriate functions (and on both earphones) at all frequencies used; listen
for proper functioning, absence of distortion, freedom from clicks, etc.
7. Check all earphones (including masking transducer) and the bone vibrator for absence of
distortion and intermittency; check plugs and leads for intermittency.
8. Check that all switch knobs are secure and that indicators work correctly.
9. Check that the subject's signal system operates correctly.
10. Listen at low levels for any sign of noise, hum, or unwanted sounds (break-through arising when
a signal is introduced in another channel) or for any change in tone quality as masking is
introduced.
11. Check that attenuators do attenuate the signals over their full range and that attenuators which
are intended to be operated while a tone is being delivered are free from electrical or mechanical
noise.
12. Check that controls operate silently and that no noise radiated from the audiometer is audible at
the subject's position.
13. Check subject communication speech circuits, if appropriate, applying procedures similar to those
used for pure-tone function.
Page 15