Northern Airborne Technology AA21-4xx - Manual (Page 22)

AA21-400 Cabin PA System Manual SM34 Rev. 4.00
Page 2-4 Nov 10, 2003
ENG-FORM: 800-0106.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
2.3.6 Adjustments
The unit ships from the factory with all internal adjustments set to the normal test levels.
Once installed in the aircraft, it may be desirable to change some of these settings to
best suit the local operating environment. The internal adjustments are accessible
through holes located on the top of the unit.
2.3.6.1 Sweep Rate
The sweep rates for the wail and yelp modes of the siren are adjustable using the
appropriately marked pots. The yelp rate is adjustable from 48 cycles/min to 300
cycles/min, and the wail rate is adjustable from 5 cycles/min to 200 cycles/min. Rotating
a pot cw will increase the sweep rate, and ccw will decrease it.
2.3.6.2 Level
Adjustments
The sidetone, mic, siren, receive, and internal speaker levels are all adjustable by
rotating the appropriate pots cw to increase the level, and ccw to decrease it. The
external speaker level is adjustable by rotating the appropriate pot cw to decrease the
level, and ccw to increase it.
The range adjustments for the potentiometers are given below:
External speaker level: (60dB dynamic range)
Internal speaker level: (90dB dynamic range)
S/T level: (100dB dynamic range)
Sweep Rate
Adjustments
Configuration
Jumpers
Level Adjustments