Airman 750/760 CMM
Maintenance 31
6. Adjust the
voltage across the headset
per Table 2.
TABLE 2.
Headset/Headphone Voltage, Speaker Wiring, and Impedance
VERSION
VOLTAGE ACROSS
HEADSET PLUG
SPEAKER
WIRING
IMPEDANCE
64300-200, -205, -208,
-218, -219, -220
64400-200
.39 VRMS
Parallel
150
64300-300
.39 VRMS
Stereo
300
64300-210, -212,
.77 VRMS
Series
600
7. Measure the
acoustic output of the headset
, using the audio analyzer
OR
the constant voltage sine wave generator.
NOTE:
Earphone sensitivity @1 kHz should be 104 ±5 dB on the earphone.
8. Measure and record the
acoustic output over the frequency range of 350Hz to 3KHz
.
NOTE:
The resultant curve should fit the limits as defined in “Description/Specifications”
on page 7.
9. Repeat steps 1 through 8 with the second speaker, if applicable.
4.4 Mechanical Maintenance
4.4.1 Cleaning the Unit
IMPORTANT:
Use a mild detergent or isopropyl alcohol wipes to clean the plastic and metal headset parts and ear
cushions (not foam windscreen). Do not soak or allow the cleaner to puddle on the unit and sit for long
periods of time. The cleaner should wipe off or evaporate quickly. Do not allow alcohol or any liquid to
touch the speaker or microphone element.
Cleaning directions here are considered for external surfaces only. Internal surfaces should not require
cleaning. The factory uses isopropyl alcohol to clean parts before shipping, if needed.
