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Summary of Contents for COBHAM 251
- Page 1 251-16-1 DOCUMENT NUMBER PASSENGER SPEAKER AMPLIFIER INSTALLATION AND OPERATION MANUAL REV "-" Sep 15, 2004 Cobham 6400 Wilkinson Drive Prescott, AZ 86301-6164 (928) 708-1500 SEALED 2011.08.16 17:15:38 -07'00' Amendment #2 Aug 9, 2011 CONFIDENTIAL AND PROPRIETARY TO COBHAM...
- Page 2 251-16-1 Rev. - 251 Passenger Speaker Amplifier Installation and Operation Manual Cobham has acquired the assets of Nothern Airborne Technology Ltd. and dB Systems Inc., and has reissued this manual in its entirety Cobham will be responsible for all future amendments and revisions.
- Page 3 251-16-1 Rev. - 251 Passenger Speaker Amplifier Installation and Operation Manual Periodically Cobham 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.
- Page 4 MANUAL AMENDMENT Manual: 251-16-1 Amendment #: 2 Document #: 251-16-1 809-0002 Amendment Date: Aug 9, 2011 The purpose of this amendment is to update the 251 outline drawing and MOD table per ECR11040. Amendment Instructions: Remove Pages Replace With Pages...
- Page 5 The purpose of this amendment is to correct the outline drawing and include the NAT information. Amendment Instructions: Remove Pages Replace With Pages 251-16-1 Title Page, rev - SM251 Title Page, rev - Pages b – c, rev - Pages b – d, rev -, Amendment #1 Page 7...
- Page 6 EQUIPMENT MANUAL 251-16-1 REV - CHANGE RECORD DATE CHANGE CHECK APPROVAL 3-11-03 ORIGINAL DOCUMENT RELEASED Amendment #1 Aug 03, 2004 Page a 251/251-16-1...
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Page 7: Table Of Contents
Table 1 Pinout Listing ........................9 Table 2 Environmental Qualification Form ...................14 Figures / Drawings Outline, Model 251-[ ], Passenger Speaker Amplifier (Rev 1.70)........7 Figure 2 Model 251-[ ] Block Diagram ...................8 Figure 3 Model 251-[ ] Wiring Diagram ..................10 Figure 4 Internal Trim Pot Adjustments..................13... -
Page 8: Table A Detail Part Numbers
-001 calibration is designed for use with 4-inch speakers. Identical to 251 Base Model. Part number 251-002 was created to prevent a conflict with an existing part number 251 in customer part system. Identical to 251 Base Model with the following exceptions: a) Briefing audio is to output through the right speaker only. - Page 9 EQUIPMENT MANUAL 251-16-1 REV - SM251 FIGURES This page lists the drawings necessary for complete maintenance and troubleshooting. The applicable serial numbers are shown in the right hand column. Previously only the most current revision of each figure was included in this manual.
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Page 10: Equipment Operations And Installation
Internal screwdriver potentiometer adjustments are accessible, after removal of the Model 251 end plate, to set the chime or ringer levels heard in the passenger speakers. Each left and right speaker amplifier output rating is 28 Watts into 2 ohms (30 Watts typical) or 49 Watts into 1 ohm. - Page 11 The operating modes of the Model 251 are established when either a ground (low) signal or a 12 to 32 VDC (high) signal is applied as listed below to the connector pin listed: Control Pin No.
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Page 12: Specifications
EQUIPMENT MANUAL 251-16-1 The amplifiers are adjusted for acceptable listening output levels into the proper loads with ADF receiver inputs of 7.75 V , stereo audio inputs of 0.45 V , PSC, TV, and Briefer audio inputs of 1.00 V and PA MIC input of 0.25 V... - Page 13 EQUIPMENT MANUAL 251-16-1 OUTPUTS: RIGHT SPEAKER: The right speaker amplifier is designed for speech and music signals. Rated power specification is the maximum power the amplifier can continuously deliver into the maximum rated load without clipping. Rated Power Load 49 W...
- Page 14 EQUIPMENT MANUAL 251-16-1 ISOLATION BETWEEN CHANNELS: 60 dB, minimum. OUTPUT NOISE: Greater than 75 dB below rated, all outputs. POWER SUPPLY: 28 VDC, 5 ampere maximum. OPERATING TEMPERATURE: From -55 to +70°C. Thermal fold back of the speaker outputs occurs if the heatsink temperature reaches 105°C.
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Page 15: Installation Procedures, Wiring Diagram, And Limitations
INSTALLATION PROCEDURES, WIRING DIAGRAM, AND LIMITATIONS PHYSICAL Installation dimensions are shown on the Model 251 outline on Figure 1. The amplifier should be mounted to a metal surface and it is necessary to ground the case to the metal aircraft structure. - Page 16 Chelton Avionics, Inc dba Wulfsberg Electronics Division Prescott,AZ Amendment #8 Page 7...
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Page 17: Figure 2 Model 251-[ ] Block Diagram
EQUIPMENT MANUAL 251-16-1 Figure 2. Block Diagram, Model 250-XXX Passenger Speaker Amplifier 251/251-16-1 Page 8... -
Page 18: Table 1 Pinout Listing
EQUIPMENT MANUAL 251-16-1 The paging and receiver volume control pots required are linear taper, zero to 10,000 ohms, 1/2 watt or greater. Electrically, the pots are wired to provide maximum resistance to the Model 251 for full volume (fully clockwise rotation). -
Page 19: Figure 3 Model 251-[ ] Wiring Diagram
EQUIPMENT MANUAL 251-16-1 Figure 3. Wiring Diagram 251/251-16-1 Page 10... - Page 20 EQUIPMENT MANUAL 251-16-1 Figure 3. Wiring Diagram (continued) 251/251-16-1 Page 11...
- Page 21 EQUIPMENT MANUAL 251-16-1 Figure 3. Wiring Diagram (continued) 251/251-16-1 Page 12...
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Page 22: Figure 4 Internal Trim Pot Adjustments
EQUIPMENT MANUAL 251-16-1 Figure 4. Internal Trim Pot Adjustments 251/251-16-1 Page 13... -
Page 23: Table 2 Environmental Qualification Form
NOMENCLATURE: Passenger Speaker Amplifier_____________________________________________________ TYPE/MODEL/PART NO.: Model 251-[ ] TSO NUMBER: TSO-C50c _______________________________ MANUFACTURER'S SPECIFICATION AND/OR OTHER APPLICABLE SPECIFICATION: dB Systems’ __________ Document No. 251-16-1, Equipment Manual _________________________________________________________ MANUFACTURER: dB Systems, Inc. ______________________________________________________________ ADDRESS: 2847 152nd Avenue N.E., Redmond, Washington 98052 __________________________________ DO-160C... - Page 24 RTCA Document DO-214, Section 2.8 were conducted on the Model 251 qualification test unit. Remarks: Model 251-[ ] was qualified to the environmental test requirements of RTCA DO-160C by similarity to Models 250-[ ] and 700-[ ].
- Page 25 This supplement contains installation and operation information that is unique to the 251-003 Passenger Speaker Amplifier . Installation and operation information common to the 251 base unit can be found in SM251 Installation and Operation Manual. Description Functional/Cosmetic Changes The 251-003 is identical to the 251 base model with the following exceptions.
- Page 26 251-003 Passenger Speaker Amplifier Manual Supplement Rev. 1.30 Installation Drawings DRAWING REV. DESCRIPTION TYPE SERIAL # 251\003\403-0 1.00 Passenger Speaker Amplifier Interconnect 251\003\403-1 1.00 Passenger Speaker Amplifier Interconnect 251\003\403-2 1.00 Passenger Speaker Amplifier Interconnect 251\003\405-0 1.00 Passenger Speaker Amplifier Connector Map...
- Page 31 SM251 Installation and Operation Manual Supplement This supplement contains installation and operation information that is unique to the 251-006 Passenger Speaker Amplifier. Installation and operation information common to the 251 base unit can be found in the SM251 Equipment Manual.
- Page 32 251-006 Passenger Speaker Amplifier SM251 Installation and Operation Manual Supplement This page intentionally left blank. Page 2 May 13, 2009 SM Supplement Rev: 1.00 ENG-FORM: 810-0111.DOT CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
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