PRODUCT SUPPORT MANUAL Y1-03-0057 (25-60-06) Overhaul Manual with Illustrated Parts List Rev. F EM-2BATM Product No. 2206 FAA PMA Approved under A3-06-1405 Portable Safety Megaphone ACR Electronics, Inc. 5757 Ravenswood Road Fort Lauderdale, Fl 33312 +1(954) 981-3333 · Fax +1 (954) 983-5087 www.acrelectronics.com Email: Info@acrelectronics.com A Chelton Group company TABLE OF CONTENTS SECTION 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0 TITLE Description Technical Data Operation Cleaning Battery Replacement Testing Trouble Shooting Disassembly Inspection Check Repair Assembly Parts List PAGE 1 1 2 4 4 4 5 6 6 6 7 9 ILLUSTRATION Figure 1 Block Diagram ACR/EM-2BA Portable Safety Megaphone Illustrated Parts List ACR/EM-2BA Portable Safety Megaphone 3 Figure 2 8 i 1 Y1-03-0057 Rev. F 1.0 DESCRIPTION 1.1 The ACR/EM-2BA is a battery operated solid state megaphone specifically developed for use in enclosed areas such as in the interior of an aircraft or ship cabin. It has been designed to minimize regenerative acoustic feedback that results in whistling and other oscillations of this nature. It has a 90° sound projection angle to direct the sound to persons in its immediate vicinity, as well as in the rear sections of any aircraft. The amplifier frequency band-pass has been selected to produce a crisp, clear reproduction of voice signals. The operating power level is also sufficient to provide adequate sound under high ambient noise level conditions without being over-powering. Specific attention has been given to the physical size so that it can be used effectively in a crowded environment. The integrated circuit amplifier only uses a small current when turned "ON". Large currents necessary to drive the speaker are utilized only on voice peaks. This extends the life of the batteries so that several hours of operation may be expected when used normally in an intermittent manner. Batteries should be replaced periodically as recommended by the manufacturer. (See section 5.0) A simplified block diagram of the megaphone is shown in Figure 1. A battery test circuit is included. A flashing green LED indicates that the battery is Ok. 1.2 1.3 2.0 TECHNICAL DATA Dimensions Weight Materials 5.5" max diameter bell, 11.5" max long 2.3 lbs., including batteries Horn, handle ­ Anodized Aluminum Housing ­ Aluminum Neck strap at top of unit Thumb operated Integrated circuit, 3 watts power output Re-entrant horn and driver type; input power five (5) watts; 90° dispersion angle Attachment Gain Control* Amplifier Speaker 2 Y1-03-0057 Rev. F Batteries Power Drain Six (6) standard 1½ volt "AA" cells 25 milliamps static current 550 milliamps maximum current 500 to 3500 Hz Visual Flashing Green LED Frequency Response Battery Test Circuits 3.0 OPERATION 3.1 To test the battery, squeeze the handle and note if the green LED (located near the volume control cap) is flashing. The batteries are useable as long as the LED flashes. Hold the megaphone in one hand. Place mouth almost in contact with the microphone mouthpiece at the rear of the assembly. Squeeze the handle, which will flex slightly, turning the megaphone "ON" and speak slowly with loud, crisp, clear tones. Adjust the volume control knob to a suitable sound level. The volume control may be adjusted with the thumb of the same hand holding the megaphone. When not in use, carry the megaphone by the neck strap, attached to top of unit. 3.2 3.4 3.5 3 Y1-03-0057 Rev. F SPEAKER ASSEMBLY AUDIO AMPLIFIER SIREN CIRCUIT & BATTERY MONITOR MEGAPHONE SUB-ASSEMBLY VOLUME CONTROL MICROPHONE ASSEMBLY - + + N.O. N.C. HANDLE SWITCH + BATTERY PACK - FIGURE 1 BLOCK DIAGRAM ACR/EM-2BA PORTABLE SAFETY MEGAPHONE 4.0 CLEANING 4.1 External surfaces of the megaphone may be cleaned with a soft cloth, dampened in a solution of mild household detergent. Do not immerse in water or use strong solvents. Clean electrical contacts with cloth dampened with isopropyl alcohol. 5.0 BATTERY REPLACEMENT (see Figure 2) 5.1 The power supply used in the megaphone consists of six standard 1 ½ volt "AA" size batteries. Current drain is minimal (25 mA) with the megaphone "ON", and increases when the user speaks into the microphone. 4 Y1-03-0057 Rev. F 5.2 Battery replacement is accomplished by removing three set screws (3) while holding the microphone and mouthpiece assembly (2) in place. The six battery cells, contained in three tubes with two cells per tube, are immediately accessible and will drop out when the megaphone is tilted. New batteries may be dropped into the tubes, observing polarity marking adjacent to each tube. Replace microphone and mouthpiece assembly (2). Align keyway and secure with the three set screws (3). CAUTION: Observe polarity of cells carefully before replacement. 5.3 6.0 TESTING Note: The megaphone consists of three major assemblies; the microphone and mouthpiece assembly, the megaphone sub-assembly, and the horn and speaker assembly. To locate a defect, follow the procedure outlined below: 6.1 6.2 Squeeze the handle. If a clicking sound is heard, the speaker is operating. If no sound is heard, remove the microphone and mouthpiece assembly and the batteries. Check that both the microphone and battery contacts are clean. If not, clean with a mild, non-abrasive cleaner such as alcohol. Test amplifier and speaker assembly by replacing the microphone with a spare microphone assembly. If no sound can be produced after microphone replacement, it may be assumed that the amplifier or speaker assembly is defective. To test the speaker, disassemble the speaker. Disconnect one wire and apply 1 ½ volts intermittently across the speaker. If no clicks are heard, the speaker is defective. 6.3 6.4 5 Y1-03-0057 Rev. F 7.0 7.1 TROUBLESHOOTING Testing procedure for locating defects is given in paragraph 6.0. Possible faults and corrections are summarized below for ready reference. TROUBLE No sound from speaker when handle is squeezed (Step 6.1) POSSIBLE CAUSE Exhausted batteries, defective microphone, speaker or amplifier assembly Exhausted batteries or wrong polarity of battery series Defective speaker CORRECTION Replace defective component Sound is abnormally low or distorted Check proper insertion of batteries or replace batteries. Replace speaker Speaker does not respond to Step 6.4 8.0 DISASSEMBLY (see Figure 2) 8.1 Megaphone should be disassembled for repair or replacement of components only. 8.1.1 Remove microphone and mouthpiece assembly (2) by removing the three set screws (3). Remove battery cells (4) from the three tubes by tilting megaphone to allow cells to drop out into the hand. Remove the three oval head screws (10) at periphery of the speaker end of the housing (14). Extract Speaker & Megaphone Subassembly by firstly turning horn (15) clockwise approximately 45°. Secondly pull the entire assembly gently until it stops. Rotate the assembly counterclockwise 45°, then pull the entire assembly out. The Speaker Assembly (6) and Megaphone Subassembly (9) can be separated by firstly unplugging the speaker wires from the "out" header and then removing the hex screw that holds the asesmbly together. 8.1.2 8.1.3 8.1.4 8.1.5 6 Y1-03-0057 Rev. F 8.1.6 Disassembly in steps 8.1.1 through 8.1.5 above is sufficient to examine the megaphone for faults and testing. Further disassembly is not recommended. 9.0 INSPECTION / CHECK 9.1 Inspect unit for any evidence of damaged parts, loose mountings or broken leads and dirty electrical contacts. 10.0 REPAIR 10.1 The megaphone consists of three major sub-assemblies; the Microphone and Mouthpiece Assembly, the Megaphone Sub-Assembly, and the Horn and Speaker Assembly. Repairs are restricted to the replacement of these defective sub-assemblies or the batteries and lanyard assemblies. 11.0 ASSEMBLY 11.1 Assembly of the megaphone is in reverse order of disassembly. Follow these instructions: 11.1.1 Align Horn (15) and Speaker Assy (6) with location pins on Megaphone Subassembly (9) 11.1.2 Attach Horn (15) and Speaker Assy (6) to Megaphone Subassembly (9). Route Speaker wires through provided slot. 11.1.3 Plug Speaker connector into the "out" header. 11.1.4 Push entire assembly gently into the Housing (14) until it stops. Turn clockwise 45° and push all the way in. Turn counterclockwise 45° and align holes. 11.1.5 Replace screws (10) 11.1.6 Replace the six batteries (4) in three tubes at microphone end of megaphone case. CAUTION: Observe polarity of batteries during installation procedure (see instructions at battery tube openings of the megaphone). 7 Y1-03-0057 Rev. F 11.1.7 Replace microphone and mouthpiece assembly (2). Align keyway, and secure with the three setscrews (3). 11.1.8 Steps 11.1.1 through 11.1.7 complete the assembly of the megaphone. After assembly, test unit in accordance with Paragraph 6.0, Testing. 8 Y1-03-0057 Rev. F FIGURE 2 ACR / EM-2BA PORTABLE SAFETY MEGAPHONE ILLUSTRATED PARTS LIST 8 12.0 PARTS LIST 12.1 Replaceable parts are illustrated in Figure 2, and listed below in the table. Part numbers shown in the "Part Number" column may be ordered from ACR unless another manufacturer's name is given in parenthesis in the "Description" column., In this case, replacement parts can be obtained directly from the original manufacturer. Standard parts (MS-, AN-, etc.) and commercially available hardware (`Commercial') should be obtained from commercial sources. NOMENCLATURE ORDER SPARE PARTS EM-2BA S/N < 2000 EM-2BA S/N 2000 #2206 9211 9416 Commercial A41-05-0562 9418 N/A N/A 9421 Commercial 9423 9233 A1-18-1151 A1-17-0809 ITEM QTY 1 2 3 4 5 6 7 8 9 10 11 12 & 13 14 15 1 1 3 6 1 1 3 2 1 3 1 1 1 1 Megaphone, Safety Microphone & Mouthpiece Assy Socket Setscrew Kit Battery AA Alkaline Hole Plug Speaker Assembly Screw Self tap (#4 x ¾) Wire leads (#26AWG) Megaphone Subassy Screw Machine (#4-40 x 3/8) Handle Kit Strap assembly Kit Housing, Megaphone Horn, Megaphone Obsolete 9211 9416 Commercial A1-05-0562 9419 (Upgrade Kit) Commercial Commercial 9419 (Upgrade Kit) Commercial 9423 9233 A1-18-1151 A1-17-0809 S/N 2000 are date coded 4/99 + 9 ...