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Model 246 Isolation Amplifier

 

SM246 Installation and Operation Manual 

 

Section 1 Rev: 1.00 

Issue 2 

Page 1-1 

ENG-FORM: 800-0113.DOT 
 

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD. 

Section 1 Description 

1.1  

Introduction 

 
Information in this section consists of product description, design features and specifications for the 
Model 246 Isolation Amplifier. All derivative product information shall be contained in the applicable 
manual supplement, which may be obtained from NAT as required. 
  
Review all notes, warnings and cautions. 

1.2  

Product Description 

 
The Model 246 Isolation Amplifier is an electronic device capable of driving 100 mWrms into a  
600 Ohm load.  It is intended as a direct replacement for the Collins model 356C-4.  The Model 246 is 
also capable of driving 5 Wrms into an 8 Ohm load. 

1.3  

Design Features 

 
The Model 246 Isolation Amplifier is based on a solid-state integrated circuit.  It has a 470 Ohm 
differential input and an output compatible with a 600 Ohm or a 4 Ohm load.  It provides an internal gain 
adjustment (accessible through a hole in the cover) of 4.5 dB to 42 dB and is capable of supplying a 
minimum of 100 mW into a 600 Ohm load.  It will drive headphones with impedance ratings of 4 to 600 
ohms.  With the unit adjusted for a gain of 40 dB, an input level of 77.5 mVrms will produce an output 
level of 7.75 Vrms (100 mW into 600 ohms.) 

1.4  

Specifications 

1.4.1  

Electrical Specifications 

 

Input 

0.0775 Vrms into 470 ohms 

 
Output 

100 mWrms into 600 ohms at <1 % distortion 

 

Microphone Bias  

15 Vdc at 30 

±

5 mA (enabled by internal jumper)

 

 
Output Noise 

70 dB below 100 mW 

 
Power Supply 

<0.5 amp at 28 Vdc, 1 A circuit breaker recommended

 

1.4.2  

Physical Specifications 

 

Height 

1.53" (38.86 mm) max 

 

 

 

 

 

Depth 

2.81" (71.37 mm) max including flanges 

 

 

 

 

 

 

 

 

Width 

2.78" (70.61 mm) max excluding connector 

 

 

 

 

 

 

 

 

Weight 

0.35 lbs (159 g)  

 

 

 

 

Содержание 246

Страница 1: ...irschner Road Kelowna BC Canada V1Y 4N7 Telephone 250 763 2232 Facsimile 250 762 3374 Issued on the authority of Northern Airborne Technology Ltd Copyright 1996 Installation and Operation Manual Model 246 Isolation Amplifier SM246 ISSUE 2 00 ...

Страница 2: ...G FORM 820 0114 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 ...

Страница 3: ......

Страница 4: ...ifications 1 2 1 4 3 Product Approval 1 2 2 Installation 2 1 Introduction 2 1 2 2 Unpacking and Inspection 2 1 2 2 1 Warranty 2 1 2 3 Continued Airworthiness 2 1 2 4 Installation Procedures 2 1 2 4 1 Warnings 2 1 2 4 2 Cautions 2 2 2 4 3 Cabling and Wiring 2 2 2 4 4 Pin Identification 2 2 2 4 5 Beech King Air Interphone Interconnect 2 3 2 4 6 Typical Collins Interconnect 2 4 2 4 7 Post Installatio...

Страница 5: ...1 3 Design Features The Model 246 Isolation Amplifier is based on a solid state integrated circuit It has a 470 Ohm differential input and an output compatible with a 600 Ohm or a 4 Ohm load It provides an internal gain adjustment accessible through a hole in the cover of 4 5 dB to 42 dB and is capable of supplying a minimum of 100 mW into a 600 Ohm load It will drive headphones with impedance rat...

Страница 6: ...cations Temperature 55 C to 70 C Altitude 70 000 ft Qualification of the Model 246 Isolation Amplifier was completed in accordance with RTCA DO 160C Environmental Categories A2F2 BA CL XXXXXXZ BZ AAATZ XXC2 XX Note Refer to Environmental Qualification Form located in Section 2 of this Manual for complete details of the environmental categories 1 4 4 Product Approval FAA TSO C50c RTCA DO 214 RTCA D...

Страница 7: ...free of defects in workmanship or performance This warranty covers all materials and labour but is exclusive of any transport to deliver the defective unit to and from NAT or its designated warranty repair center or any labour to remove or re install the defective unit in the aircraft Contact NAT for any questions regarding this warranty its applicability to your units and or for return authorizat...

Страница 8: ...onnector hood to be easily installed Reference the interconnect drawing in Section 2 7 for shield termination details Maintain wire segregation and route wiring in accordance with the original aircraft manufacturer s Maintenance Instructions The input pins A B and C should be wired using 22 to 24 AWG shielded cable The shield is attached to the airframe at one end only The output pins D and E and ...

Страница 9: ...n Amplifier SM246 Installation and Operation Manual Section 2 Rev 1 00 Issue 2 Page 2 3 2 4 5 Beech King Air Interphone Interconnect ENG FORM 805 0115 DOT CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD ...

Страница 10: ...lation Amplifier SM246 Installation and Operation Manual Section 2 Rev 1 00 Issue 2 Page 2 4 2 4 6 Typical Collins Interconnect ENG FORM 805 0115 DOT CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD ...

Страница 11: ... conducting audio tests and slowly increase the headset volume level to a comfortable listening level Power up the aircraft s systems and verify normal operation of all functions of the model 246 Upon satisfactory completion of all performance checks make all required log book entries electrical load weight and balance amendments and other documentation as required by your local regulatory agency ...

Страница 12: ...may be connected between pins A and B or pins C and B This makes the Model 246 compatible with the Model 210 Voice Activated Switch Note The Collins unit provides only 5 mA bias current When jumper J1 is connected between P2 pins 1 and 2 closest to connector the microphone bias current is enabled When it is connected between pins 2 and 3 furthest from the connector it is disabled Pin 3 Pin 2 Pin 1...

Страница 13: ...This page intentionally left blank ...

Страница 14: ......

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Страница 16: ...ory XXC2 Lightning direct effect 23 0 Category X no test required Icing 24 0 Category X no test required REMARKS Tests of DO 160C Sections 6 0 7 0 and 8 0 were conducted at Northern Airborne Technology Ltd NAT in Kelowna BC on Model 246 Tests of DO 160C Sections 16 0 and 18 0 were conducted at dB Systems Inc in Redmond WA on Model 246 Tests of DO 160C Sections 4 0 paragraphs 4 5 1 4 5 2 4 5 3 and ...

Страница 17: ... Model 246 Isolation Amplifier 3 2 General Information The Model 246 Isolation Amplifier is an electronic device capable of driving 100 mWrms into a 600 Ohm load It is intended as a direct replacement for the Collins model 356C 4 The Model 246 is also capable of driving 5 Watts RMS into an 8 Ohm load The Model 246 Isolation Amplifier has no operator accessible controls During installation it may b...

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