Mark IV Electro-Voice 903E User manual

SPECIFICATIONS
(Per RTCA/DO-170)
Generating Element:
Electret Condenser
Frequency Response:
300-5,000 Hz - see Figure 1
Polar Pattern:
Pressure gradient
(differential close-talking)
Impedance:
Matches standard aircraft
carbon circuitry
DESCRIPTION
The Electro-Voice model 903E condenser
handheld microphone iS designed for use m
high noise environments where high speech
intelligibility is desired such as in aircraft
cockpits, passenger cabins, control towers or
terminal areas.
The electret element virtually eliminates EMI,
RFl. and magnetic signals channeling the full
power of your communications system into
crisp, articulate voice transmission with the
RTCA frequency response.
Sensitivity:
400 mV ±3 dB for
114 dB re 20/i pascals
(normal speech)
(output of built-in amplifier)
Power Requirements.
See test circuit Figure 3
(operates into carbon microphone circuit)
Current Drain:
11 ma at 8 V dc (12-volt system)
27 ma at 16 V dc (24*volt system)
Case Material:
Black A3S
Dimensions:
91.5 mm (3.6 in,) length, less hanger
61.0 mm (2.4 in.) width
35.6 mm (1.4 in.) depth
Weight:
180 grams
Accessories Supplied:
Panel mounting bracket (8474)
Certification;
FAA TSO C-58a
The microphone is recommended for
advanced technology air transports
employing electronic flight insUumentation
systems (glass cockpits). Its proven electret
technology will not decay or deteriorate in
any way over extended periods.
Features:
• Highly reliable
• EMI and RFl protected
• Tailored voice response tor
high articulation per RTCAyDO-l70
• Immune to aircraft generated
magnetic fields
• Greater durability
• Lightweight
• 903-1341 (with PJ-068 connector)
• 903-1342 (with A4M connector)
WARRANTY (Limited)
Electro-Voice .Aircraft Microphones are
guaranteed for a period of thirty-six m.onths
from date of original purchase acamst
malfunction due to defects in workmarsnip
and materials. If such malfunction occurs,
microphone will be repaired or replaced (at
our option) without charge for materials or
labor if delivered prepaid to the proper
Electro-Voice service facility Unit will be
returned prepaid Warranty does not extend
to finish, appearance itemis. cables, cade
connectors, switches or malfunction due to
abuse or operation under other than
specified conditions, nor does it extend to
incidental or consequential damages Some
states do not allow the exclusion or limitation
of incidental or consequential damages, so
the above exclusion may not apply to you
Repair by other than Electro-Voice or its
authorized service agencies will void this
guarantee. This warranty gives you specific
legal rights, and you may also have other
rights which vary from state to state
Service and repair address for this product:
Electro-Voice. Inc.. 600 Cecil Street.
Buchanan, Michigan 49107.
Specifications subject to change
without notice

REPAIR INSTRUCTIONS
1 Special Tools: None.
2 Disassembly; (See Figure 5)
a. Remove 4 rear screws, holding front
and rear case halves together.
b Mic head assembly will slip out of front
case
c. Switch plate has to be removed if
cable S/A is to be removed
3. Inspection:
a Inspect switch contacts for signs of
excessive wear,
b. Examine unit for damaged or dned-oul
wiring or sleeving. Check all solder
connections for good contacts.
c. Check cable for signs of damage such
as cuts or cracks.
4. Repair and Replacement:
a. Replace any part which is damaged.
b. The mic head assembly is sealed and
not repairable—replace entire
assembly (EV#81393) if defective.
5 Reassembly: Reverse Step 2 above
6 Check of Microphone Output:
The eieciret microphone has the carbon
equivalent circuit inside the head
assembly A speech output of approx¬
imately 0.2 volts should be obtained when
used with the DO-170 test circuit or an
aircraft intercom.
7 Performance to Specifications
a Electrical conformance to DO* 170
requires special equipment and an
artificial voice.
b. Certification can only be given by the
Electro-Voice Service Center in
Buchanan, Michigan.
c If proof of performance and/or
certification is required, send the unit
to the warranty address on Page 1

ITEM
PART NO.
REQ’O.
DESCRIPTION
1
A72319-RL
1
From Case
2
75241
4
Inse't
3
75993 AY 1
Pivot Pm
4
75992-AY
1
Switch Piaie
5
7599IRL
1
Actuator
6
62607-AO
1
Screw. Pan Head, Phillips
7
56065
1
Leaf Switch
8
L60126-AP 2
Screw Binding Head. Phillips
9
4067-AD
1
Lock Washer
10 19048-AD
1
Spring
11
38283
1
RuOber Gasket
12
48875
1
Nameplate
13
A72318
1 Foam Spacer
14
X48559
1 Nameplate (903-1342)
W40559
1
Nameplate (903*1341)
15
C60024-AD
4
^rews. #2
16
72570-RL
1
Case Back
17 62608
2
Screw. Filled Kead Slotted
18
81393
1
Microphone S/A
19
62609
2
Screw. Filled Head. Slotted
20
27057
1
Lug
21
81489
1
Cable S/A with A4M
(903-1342)
81488
1
Cable S/A with PJ-068
(903-1341)
22
8474
1
Mounting Bracket

ENVIRONMENTAL QUALIFICATION FORM
MICROPHONE, ELECTRET, (HANDHELD 903E & 913E), (BOOM MOUNTED 978E)
MODELS; 978E, 903E & 913E TSO NUMBER: TSO-C58a
Specifications Enclosed with Microphones
CONDITIONS
DO-160B
PARAGRAPH #
DESCRIPTION OF CONDUCTED TESTS
Temperature and Altitude
Low Temperature
High Temperature
Altitude
Decompression
Over Pressure
4.0 Rev. 1
4.5.1
4 5.2. 4 5.3
46.1
4 6.2
4 63
Equipment tested to Category B1
Decompression tested at 53.000 ft.
Temperature Variation
5.0
Equipment tested to Category B
Humidity
6.0
Equipment tested to Category's. Level 1
Shock
Operational
Crash Safety
7.0
7.2
7.3
No test required
Vibration
8.0
Equipment tested without shock mounts to
Categories K & S (DO-160B. Table 8-1)
Explosion
90
No test required
Waterproofness
100
No test required
Fluids Susceptibility
11 0
No test required
Sand and Dust
12.0
No test required
Fungus
13 0
No test required
Salt Spray 14.0 No test required
Magnetic Effect 15.0
Equipment tested as Class B'
Power Input
16.0
No test required
Voltage Spike Conducted
17.0
Equipment tested to Category A’
Audio Frequency Conducted
Susceptibility
18.0
No test required
Induced Signal Susceptibility^
19.0
Equipment tested to Category B'
Radio Frequency Susceptibility^
20 0
Equipment tested to Category *B'
Radio Frequency Emmission^
21 0
Equipment tested to Category *6’
Other Test2
Fire resistance tests were conducted in accordance
with Federal Aviation Regulation. Part 25.
Appendix F, F A R 25.853 and F A R 25 1359 (d)
REMARKS
— Tests were performed at Electro*Voice. Inc., Sevierville. TN. except the following:
^Radiometrics Midwest Corp, Lombard. IL
2Gaynes Testing Laboratories. Chicago. IL
ELECTRO-VOICE, INC., 600 Cecil Street. Buchanan, Michigan 49107
VANLFACTURING PLAfsrrS at ■ BUCHANAN mi ■ NEV/PORT. TN ■ SEVIERVILLE TN ■ REDMOND WA ■ GANANOOUE ONT
Pan Number 531409—939
©Eiearo-voice, inc. 1989 ■ LittTO In US A
-a MARK IV conipany.