Nat SM245 User manual

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
SM245
245 Speaker Amplifier
INSTALLATION AND OPERATION MANUAL
REV 4.10 June 23, 2005
Northern Airborne Technology Ltd.
1925 Kirschner Road
Kelowna, BC, Canada.
V1Y 4N7
Telephone [phone]
Facsimile [phone]
Copyright 2005 by Northern Airborne Technology

SM245 Rev. 4.10 Model 245 Speaker Amplifier Manual
Jun 23, 2005 Page ii
ENG-FORM: 820-0110.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
Northern Airborne Technology Ltd.
has acquired the assets of dB Systems Inc.,
and has revised and reissued this manual in
standard NAT format.
Northern Airborne Technology Ltd.
will be responsible for all future
amendments and revisions.

SM245 Rev. 4.10 Model 245 Speaker Amplifier Manual
Jun 23, 2005 Page iii
ENG-FORM: 820-0110.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
Periodically NAT will release manual amendments. In order to maintain the most
accurate and up to date manual these amendments should be carried out immediately
upon receipt and recorded on the following amendment record.
AMENDMENT RECORD
Amendment
Number
Amendment
Date
Section(s)
Changed
Date
Entered
Entered By
1 Jul 19/06 2
Insert any Amendment Instruction sheets after this page.
Performed at factory

INSTALL_OPS
MANUAL AMENDMENT
Manual: SM245 Amendment #: 1
Document # SM245\Install_Ops\809-0001 Amendment Date: Jul 19, 2006
Amendment # 1 Jul 19, 2006 Page 1
ENG-FORM: 809-0109.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
The purpose of this amendment is to add the latest drawing revisions to the manual.
Amendment Instructions:
1 Remove Pages Replace With Pages
2-3 to 2-4 Rev 4.10 2-3 to 2-4 Rev 4.10 Amendment #1
2 Remove Drawings (Section 2) Replace or add Drawings (Section 2)
245\245\922-0 Rev 1.00 245\245\922-0 Rev 1.01
Note: Ensure that all drawings are inserted in the order shown on the latest drawing lists.
3 Update the Amendment Record sheet at the front of the manual.
4 Insert this page into the manual after the Amendment Record sheet (page iii).
Manual Amendment ends after the following amended pages

SM245 Rev. 4.10 Model 245 Speaker Amplifier Manual
Jun 23, 2005 Page iv
ENG-FORM: 820-0110.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
Table of Contents
Section Title Page
1 Description
1.1 Introduction 1-1
1.2 Purpose of Equipment 1-1
1.3 Features 1-1
1.4 Specifications 1-1
1.4.1 Electrical Specifications 1-1
1.4.2 Physical Specifications 1-2
1.4.3 Environmental Specifications 1-2
1.5 Unit Nomenclature 1-2
2 Installation
2.1 Introduction 2-1
2.2 Unpacking and Inspection 2-1
2.2.1 Warranty 2-1
2.3 Installation Procedures 2-1
2.3.1 Warnings 2-1
2.3.2 Cautions 2-2
2.3.3 Cabling and Wiring 2-2
2.3.4 Mechanical Installation 2-2
2.3.5 Post-Installation Checks 2-3
2.3.6 Log Entries 2-3
2.4 Continued Airworthiness 2-3
2.5 Accessories Required But Not Supplied 2-3
2.6 Installation Drawings 2-4
3 Operation
3.1 Introduction 3-1
3.2 General 3-1
3.3 Operation Specifics 3-1

SM245 Rev. 4.10 Model 245 Speaker Amplifier Manual
Section 1 Description
1.1 Introduction
This manual contains information on the Model 245 Speaker Amplifier. Information on
the 245-001 and 245-002 is included; all other derivative products (245-xxx) will be
covered by manual supplements, which can be obtained from NAT as required.
Information in this section consists of purpose of equipment, features and specifications.
1.2 Purpose of Equipment
The Model 245 is a Speaker Amplifier that is capable of driving a 4-ohm cockpit
speaker. It is intended to be a direct replacement for the Collins model 356F-3.
1.3 Features
The Model 245 is rated at 18 watts into a 4 ohm load. This is a peak rating intended for
speech and music. The continuous rating of the amplifier is 10 watts into 4 ohms, sine
wave.
For proper heat dissipation, the unit should be mounted to a metal surface of at least
100 square inches.
1.4 Specifications
1.4.1 Electrical Specifications
Power Supply 2.5 amps max @ 27.5 Vdc.
A 5 A circuit breaker is recommended
Input: 7.75 Vrms into 600 ohms (245 base unit only)
Speaker Output 18 Watts into 4 ohms @ <1 % distortion (rated power)
25 Watts into 8 ohms @ <1 % distortion (rated power)
Output Noise -70 dB below 10 watts
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CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

Model 245 Speaker Amplifier Manual SM245 Rev. 4.10
Page 1-2 Jun 23, 2005
ENG-FORM: 800-0108.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
1.4.2 Physical Specifications
Height 2.12" (53.9 mm) max
Depth (excl. connectors) 3.00" (76.2 mm) max, excluding flanges
3.85" (97.8 mm) max, including flanges
Width 3.60" (91.4 mm) max
Weight 0.60 lbs (0.3 Kg) max
1.4.3 Environmental Specifications
Operating Temperature -55oto +70oC
Operating Altitude 70,000 feet
Qualification ENV. CAT. [A2F2]-BA(CL)XXXXXXZ(BZ)AAATZ(XXC2)XX
Tested under environmental conditions and test procedures in accordance
with RTCA DO-160C and qualified to the categories listed in the
Environmental Qualification Form in Section 2 of this manual.
TSO Compliance: TSO-C50c, RTCA DO-214
1.5 Unit Nomenclature
Any derivatives of the Model 245 base unit are represented as Model 245-xxx, where xxx
represents the specific derivative. All differences between the base unit and the -001 and
-002 derivatives are shown below.
Model Specification Differences
245 Base Model Standard Input (7.75 Vrms into 600 ohms).
245-001 Input is 1.0 Vrms into 1800 ohms.
245-002 Input is 0.25 Vrms into 1600 ohms.
End of section 1

SM245 Rev. 4.10 Model 245 Speaker Amplifier Manual
Section 2 Installation
2.1 Introduction
Information in this section consists of unpacking and inspection procedures, installation
procedures, post-installation checks, and installation drawings.
2.2 Unpacking and Inspection
Unpack the equipment carefully and locate the warranty card. Inspect the unit visually
for damage due to shipping and report all such claims immediately to the carrier
involved. Note that each unit should have the following:
- Model 245 Speaker Amplifier
- Warranty Card
- Operator’s Manual
- Release certification
Verify that all items are present before proceeding and report any shortage immediately
to your supplier.
2.2.1 Warranty
Complete the warranty card information and send it to NAT when the installation is
complete. If you fail to complete the warranty card, the warranty will be activated on
date of shipment from NAT.
Note: An appropriately rated facility, e.g. Certified Aircraft Repair Station, must install
this equipment in accordance with applicable regulations. NAT Ltd’s warranty is
not valid unless the equipment is installed by an authorized NAT Dealer. Failure
to follow any of the installation instructions, or installation by a non-certified
individual or agency will void the warranty, and may result in a non-airworthy
installation.
2.3 Installation Procedures
2.3.1 Warnings
Do not bundle any lines from this unit with transmitter coax lines, or AM audio
rectification may result. Do not bundle any input or output audio, or DC power lines
from this unit with 400 Hz synchro wiring or AC power lines. Do not position this unit or
wiring from this unit next to any device with a strong alternating magnetic field such as
an inverter, or significant audio interference will result.
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Model 245 Speaker Amplifier Manual SM245 Rev. 4.10
2.3.2 Cautions
In all installations, use shielded cable exactly as shown and ground as indicated.
Significant problems may result from not following these guidelines, especially with
regard to ground loop noise.
2.3.3 Cabling and Wiring
All unshielded wire shall be selected in accordance with AC43.13-1B Change 1,
Paragraphs 11-76 through 11-78. Wire types should be 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 wiring diagrams in Section 2.6 as required.
Allow 3 inches from the end of the wire to the shield termination to allow the backshell to
be easily installed.
2.3.3.2 Pin Identification
The following table specifies the functions of the connector pins.
PIN # FUNCTION
A + SIGNAL INPUT
B SIGNAL GROUND
C - SIGNAL INPUT
D - OUTPUT
E + OUTPUT
F POWER GROUND
G + 28 VDC IN
Connection to the unit should be made with twisted pair, shielded cable. The shield
should be attached to the airframe at one end only. Pins A, B, and C (the input pins)
should be wired using 22 - 24 AWG wire. The output (pins D and E) and power (pins F
and G) should be wired using wire no smaller than 20 AWG.
The finish on the case is electrically conductive, and it is not necessary to remove the
finish for electrical bonding.
Caution: do not connect the audio outputs to power return or chassis ground.
2.3.4 Mechanical Installation
The Model 245 may be mounted in any position. No shock or vibration isolators are
required.
For proper heat dissipation, the Model 245 should be mounted on a metal surface of at
least 100 square inches. The amplifier case should also be grounded to the airframe.
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CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

SM245 Rev. 4.10 Model 245 Speaker Amplifier Manual
Jun 23, 2005 Page 2-3
ENG-FORM: 805-0108.DOT Amendment # 1 Jul 19, 2006
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
2.3.5 Post-Installation Checks
If any preset requires adjustment, be sure this is carried out before the aircraft leaves,
and that the unit and its mating connector are secured before departure. Make all
required log book entries, electrical load, weight and balance amendments and other
paperwork as required by your local regulatory agency.
2.3.5.1 Voltage/resistance checks
Do not attach the Model 245 until the following conditions are met.
Check the following:
a) Check pin <G> for +28 Vdc relative to ground.
b) Check pin <F> for continuity to ground - less than 0.5 Ω(power ground).
c) Check inputs and outputs for correct orientation.
2.3.5.2 Power On checks
Install the Model 245 and power up the aircraft’s systems. Verify normal operation of all
functions.
2.3.6 Log Entries
Upon satisfactory completion of all performance checks, make the required log
entries and complete the necessary Regulatory Agency paperwork before
releasing the aircraft for service.
2.4 Continued Airworthiness
Maintenance of the Model 245 is ‘on condition’ only. Periodic maintenance of this
product is not required.
2.5 Accessories Required But Not Supplied
Electrical connections to the amplifier are made via a 7-pin circular connector. The
mating connector is Amphenol part number MS3106F-16S-1S or equivalent.

Model 245 Speaker Amplifier Manual SM245 Rev. 4.10
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ENG-FORM: 805-0108.DOT Amendment # 1 Jul 19, 2006
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
2.6 Installation Drawings
DRAWING REV. DESCRIPTION TYPE
Interconnect - Speaker Amplifier Generic Interconnect
245\521-0 1.00 Speaker Amplifier Environmental Qual Form
245\245\922-0 1.01 Speaker Amplifier Mech. Installation
Section 2 ends after these Drawings

Interconnect