Maintenance; General Maintenance Procedures - Interacoustics AT235 Instructions For Use Manual

AT235 Instructions for Use - EN

4 Maintenance

4.1 General Maintenance Procedures

Routine checking (subjective tests)
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.
General
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.
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