ACR Electronics EM-1A User Manual

PRODUCT

SUPPORT

MANUAL

Y1-03-0014

(25-60-01) Overhaul Manual with Illustrated Parts List

Rev. R

EM-1A, EM-1D™

Product No. 2204, 2208

FAA PMA Approved under A3-06-1402-

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-1A & EM-1D
	Portable Safety Megaphone
Figure 2	Illustrated Parts List	8
	ACR/EM-1A & EM-1D
	Portable Safety Megaphone

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1.0DESCRIPTION

1.1The ACR/EM-1A, 1D 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 EM-1A & EM-1D are the same except for installed options:

OPTIONS MATRIX

MODEL	MANUAL GAIN	ALARM ACTUATOR	BATTERY MONITOR
			Visual	Audible
EM-1A	Yes	Yes	Yes	No
EM-1D	Yes	No	Yes	Yes

1.2The 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.

2.0TECHNICAL 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

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Gain Control*	Thumb operated
Amplifier	Integrated circuit, 2 watts power output
Speaker	Re-entrant horn and driver type;
	input power five (5) watts;
	90° dispersion angle
Microphone	High Sensitivity
Batteries	Six (6) standard 1½ volt “AA” cells
Power Drain	25 milliamps static current
	550 milliamps maximum current
Frequency Response	500 to 3500 Hz
Anti-Removal Alarm*	Warbling tone 500 – 1200 Hz
Alarm Actuator*	Plug pin, retained by nylon cord
Battery Test Circuits	Visual Flashing Green LED*
	Acoustical Beep*

*Optional feature (see options matrix)

3.0OPERATION

3.1A siren, incorporated into the megaphone, is automatically activated by unplugging the alarm plug pin.*

Note: A long lanyard with an alarm plug pin is supplied with the megaphone for use as an anti-theft alarm (optional).

3.2Squeezing the handle automatically stops the siren, and the megaphone is ready for use. Re-insert the alarm pin so that alarm will not be reactivated when pressure on the handle is removed.

3.3Hold 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.

Megaphones without the optional gain control knob are preset to a standard level via control under access hole plug.

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