Interacoustics AC40 - Checklist for Calibration

AC40 Service Manual Page 30
Checklist for calibration
Functional checks A /NA Pass/Fail
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.