37
Maintenance and service
6.3 Weekly function check
Visual check
1. Visually check the following condition of the device:
□
All the operating controls are smooth running, nothing is bent or overtorqued,
plug, power supply and accessory cables are not damaged; there are no signs of
ageing.
□
The headphone ear cushions have no cracks, breaks or any signs of ageing.
Replace if necessary.
□
The headphone fits perfectly and does not slip. All the joints move freely.
□
The serial number of the device (SN) is indicated on the headphones and bone
vibrator. If the serial number on the transducer does not correspond to the
serial number on the audiometer then you cannot use the transducer with that
audiometer! SN headphone: _______________________
SN bone vibrator: __________________________ SN audiometer:
_______________________
2. Switch on the device and wait for at least 5 minutes. The device must warm-up.
Checking tone audiometry
3. Check subjectively the hearing threshold via air conduction and bone conduction.
□
The hearing threshold is within normal limits.
4. Test the following condition at levels just above the hearing threshold:
□
No disturbing noises, no signal from other channels, no difference in the tone
quality when the masking noise is switched on.
□
dB splitter - weakening is ok
□
dB splitter without mechanical and electrical noises
□
Tone switch (mute button) mechanically silent
□
The emitted noise from the audiometer cannot be heard by the test person
5.
Test the following condition at
60 dB HL
air conduction and
40 dB HL
bone conduc-
tion:
□
Proper function on both sides of the headphone / free field speakers and bone
vibrator by all frequencies and settings, distortion-free, no switch noises, no
cross-talk of the channels, no humming or other disturbing noises.
□
Signal is not interrupted, even if the cable is moved.
6.
Test the patient response button:
□
Patient response button can be pressed, the signal is displayed
Checking speech audiometry
7. Check the following condition of the device:
□
The level meter is at the set point (0 dB HL on the VU meter for speech-simu-
lating noise or CCITT noise of the speech CD).
□
Speech signal and masking noises by levels just above the hearing threshold.
□
No disturbing noises on all sound transducers (e.g. intrinsic noise from the
playback device or the drone of the device).
□
No „cross-talk“ from another channel (e.g. left signal can be heard on the right).
□
No change in the tone quality when the masking noise is switched on, fader
weakens the speech and masking signal over the entire dB splitter range.
8. Test the following condition at
50 dB HL
air conduction and
30 dB HL
bone conduc-
tion:
□
Proper function and no distortion
□
Test signals and test person response can be heard perfectly at the audio-
metrist's place.
Date
Signature
