Checklist For Calibration - Interacoustics AC40 Service Manual

AC40 Service Manual

Checklist for calibration

Functional checks

Visual inspection, safety - Check power cord and accessory cords for
signs of wear or damage and general physical condition of
instrument.

Headband – Tension.

Cushions - Check condition; replace if needed.

Patch cords - Check plugs and leads for intermittency.

Patient response - Check for proper operation.
Pure-tone electroacoustic measurements

Frequency (Hz) - Actual measurement recorded (all frequencies).

Distortion (%) - Recorded as a percentage of THD on all frequencies.

Output levels (all transducers) - Recorded as a deviation from
standard

Linearity of all channels (all transducers) (dB) - Recorded as a
deviation from standard.

Rise/fall time (m/sec) - Actual measurement recorded.

Overshoot (dB) - Actual measurement recorded.

On/off ratio - Measured and recorded in dB down.

Crosstalk - Measured and recorded in dB down.

Pulse tones - Duration (m/sec) - Actual measurement recorded
(pass/fail).

SISI - Indicate pass or fail and deviation from standard.

Unwanted noise check - Record with (pass/fail):

Interrupter switch

Switch sounds

Mechanical sounds
Masking measurements

Narrow band noise output level - Measured and recorded as deviation
from standard, all transducers.

White noise output level - Measured and recorded as deviation from
standard, all transducers.
Speech electroacoustic measurements

Speech output level - Signal applied to input, VU meter at zero -
Measured and recorded as deviation from standard, all transducers.

Speech through external inputs - CD / tape / phono - VU meter at
zero - Measured and recorded as deviation from standard all
transducers.

Distortion - Recorded as percentage of THD.

Speech noise - Output measured and recorded as deviation from
standard.
Sound field measurements

Warble/FM output level - Actual measurement recorded (all
frequencies) as deviation from standard.

Speech inputs in sound field output level - Signal applied to input, VU
meter set at zero – Measured and recorded as deviation from
standard.

Narrow band noise output level - Measured and recorded as deviation
from standard, all transducers.

Speech/white noise output level - Measured and recorded as
deviation from standard, all transducers.

Distortion - Recorded as percentage of THD.
Operation of instrument should be checked for normal function post calibration.
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A /NA Pass/Fail