ACR Electronics EM-2BA User Manual

PRODUCT

SUPPORT

FAA PMA Approved under A3-06-1405

EM-2BA™

MANUAL

Y1-03-0057

(25-60-06)

Overhaul Manual

with Illustrated Parts List

Rev. F

Product No. 2206

Portable Safety Megaphone

ACR Electronics, Inc.

5757 Ravenswood Road

Fort Lauderdale, Fl 33312

[phone] • Fax [phone]

www.acrelectronics.com

Email: [e-mail]

A Chelton Group company

TABLE OF CONTENTS

SECTION TITLE PAGE

1.0 Description 1

2.0 Technical Data 1

3.0 Operation 2

4.0 Cleaning 4

5.0 Battery Replacement 4

6.0 Testing 4

7.0 Trouble Shooting 5

8.0 Disassembly 6

9.0 Inspection Check 6

10.0 Repair 6

11.0 Assembly 7

12.0 Parts List 9

ILLUSTRATION

Figure 1 Block Diagram 3
ACR/EM-2BA Portable Safety Megaphone

Figure 2 Illustrated Parts List 8
ACR/EM-2BA Portable Safety Megaphone

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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.

1.2 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.

1.3 A battery test circuit is included. A flashing green LED indicates that the
battery is Ok.

2.0 TECHNICAL DATA

Dimensions 5.5” max diameter bell, 11.5” max long

Weight 2.3 lbs., including batteries

Materials Horn, handle – Anodized Aluminum
Housing – Aluminum

Attachment Neck strap at top of unit

Gain Control* Thumb operated

Amplifier Integrated circuit, 3 watts power output

Speaker Re-entrant horn and driver type;
input power five (5) watts;
90° dispersion angle

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Y1-03-0057 Rev. F

Batteries Six (6) standard 1½ volt “AA” cells

Power Drain 25 milliamps static current
550 milliamps maximum current

Frequency Response 500 to 3500 Hz

Battery Test Circuits Visual Flashing Green LED

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.

3.2 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.

3.4 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.

3.5 When not in use, carry the megaphone by the neck strap, attached to top of
unit.

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Y1-03-0057 Rev. F