Model 240 Passenger Speaker Amplifier
SM240 Installation and Operation Manual
Section 2 Rev: 1.01
Issue
4
Page 2-2
ENG-FORM: 805-0121.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
2.4.1
Warnings
WARNING:
High volume settings can cause hearing damage.
Set the headset volume control to the minimum volume setting prior to
conducting tests, and slowly increase the headset volume to a
comfortable listening level.
2.4.2
Cautions
CAUTION:
Do not remove components from the product while the unit is turned on. This
could cause damage to the component or unit.
2.4.3
Cabling and Wiring
All wire shall be selected in accordance with the original aircraft manufacturer's Maintenance Instructions
or AC43.13-1B Change 1, Paragraphs 11-76 through 11-78. Unshielded wire types shall qualify to
MIL-W-22759 as specified in AC43.13-1B Change 1, Paragraphs 11-85, 11-86, and listed in Table 11-11.
For shielded wire applications, use Tefzel MIL-C-27500 shielded wire with solder sleeves (for shield
terminations) to make the most compact and easily terminated interconnect. Follow the Installation Wiring
Diagram in Section 2.7 as required.
Allow 3" from the end of the shielded wiring to the shield termination to allow the connector hood to be
easily installed. Maintain wire segregation and route wiring in accordance with the original aircraft
manufacturers Maintenance Instructions.
Maintain wire segregation and route wiring in accordance with the original aircraft manufacturers
Maintenance Instructions.
Unless otherwise noted, all wiring shall be a minimum of 24 AWG, except power and ground lines, and
speaker amplifier outputs (P40 pins 1 – 14, 18, 19, 20 and 25), which shall be a minimum of 20 AWG.
Refer to the Installation Wiring Diagram for additional specifications.
The control switches shown will switch low current loads and should have a DC rating of 28 Vdc. Typical
switches for this application include Alco MTA series.
2.4.4 Mounting
The Model 240 may be mounted in any orientation. Shock or vibration isolators are not required.
Installation dimensions are shown on the Model 240 Outline drawing. The amplifier may be mounted to a
metal or plastic surface, but it is necessary to ground the case to the airframe. When mounting to a plastic
surface, use a grounding strap. The case is finished with an electrically conductive film so it is not
necessary to remove the film for electrical bonding.
