Telex Airman 850 User manual

Airman 850
AIRMAN 850 Headset
en Customer maintenance manual

Airman 850 Table of contents | en 3
Bosch Security Systems LLC Customer maintenance manual 09-2021 | V07 | F.01U.264.819
Table of contents
1General information 5
1.1 Purpose of manual 5
1.2 Technical support 5
1.3 Parts ordering 5
1.4 Repairs 5
2Description 6
2.1 General description 6
2.2 Models covered 6
3Disassembly / Assembly 8
3.1 Disassembly 8
3.1.1 Remove cushions (Item 3) 8
3.1.2 Remove faceplate assembly (item 4) 8
3.1.3 Remove sleeve (item 8) 8
3.1.4 Remove boom assembly / cover (item 13) 9
3.1.5 Removing the circuit board (item 9 or 10) 9
3.1.6 Removing the housing (item 6 or 7) or temple plate assembly (item 15 or 16) from the
headband assembly (item 1)
9
3.1.7 Removing the glider assemblies (item 2) and glider springs (item 18) 9
3.2 Assembly 10
4Parts list 13
4.1 General 13
4.2 Airman 850, catalog number 301317-000; -002; -101; -200; -201; -300; and -400 13
5Wiring diagrams 16
5.1 Airman 850 wiring diagram (catalog numbers 301317-000; -002; -003; -101; and -400) 16
5.2 Airman 850 wiring diagram (catalog numbers 301317-200; -201; and -300) 17
5.3 Connector views / wiring diagrams 18
5.3.1 Connector view for catalog numbers 301317-000; -003; -200; -300; and -400 18
5.3.2 Connector view for catalog numbers 301317-101; and -201 18
5.3.3 Connector view for catalog number 301317-002 18
5.3.4 Connector wiring diagram for catalog numbers 301317-000; -003; -101; -200; -201; -300;
and -400
18
5.3.5 Connector wiring diagram for catalog number 301317-002 (5-pin XLR) 19
6Maintenance 20
6.1 Microphone validation and adjustment 20
6.1.1 Microphone / amplifier sensitivity check 20
6.1.2 Microphone sensitivity adjustment 21
6.1.3 Troubleshooting mic failure 21
6.2 Operational test of the microphone and headphone 23
6.3 Speaker validation and adjustment 23
6.3.1 Speaker sensitivity and frequency response verification 23
6.4 ANR validation and adjustment 24
6.4.1 Active noise reduction (ANR versions only) 24
6.4.2 Minimum attenuation requirements (linearize between points) 25
6.4.3 ANR test procedure 25
6.5 Cleaning the unit 27
7Troubleshooting 28
7.1 Troubleshooting chart 28
8Specifications 29

4en | Table of contents Airman 850
09-2021 | V07 | F.01U.264.819 Customer maintenance manual Bosch Security Systems LLC
9Appendices 31

Airman 850 General information | en 5
Bosch Security Systems LLC Customer maintenance manual 09-2021 | V07 | F.01U.264.819
1 General information
1.1 Purpose of manual
This manual, Bosch part number F.01U.264.819, contains information for the overhaul and
servicing of the Airman 850 headset.
1.2 Technical support
A liaison between the customer and factory is provided by the Bosch Product Support
Department. Consultation and assistance on technical problems, part information, and
availability of local and factory repair facilities is available. When writing, include all
information concerning problem and mail to:
Bosch Communications, LLC
8601 Cornhusker Hwy
Lincoln, NE 68506 U.S.A.
Attn: Aircraft Product Support Mgr.
Telephone: 877863 4188
1.3 Parts ordering
Replacement parts may be ordered from our parts department. When ordering, please include
the following information:
– Model number
– Part description
– Part number
– Quantity
Mail to:
Bosch Communications, Inc.
8601 Cornhusker Hwy
Lincoln, NE 68507 U.S.A.
Attn: Parts department
Telephone: 800553 5992
Fax: 402467 3279
E-mail: [email protected]
1.4 Repairs
In order to maintain the FAA certification, all repairs to the headset must be made only by
persons authorized under Part 43 of the Federal Aviation Agency regulations. Bosch offers full
support and repair.

6en | Description Airman 850
09-2021 | V07 | F.01U.264.819 Customer maintenance manual Bosch Security Systems LLC
2 Description
2.1 General description
The Telex Airman 850 is a lightweight aviation headset complete with a boom-mounted, noise-
canceling electret microphone.
Lightweight design with soft, pliable cushions, adjustable headband, extended frequency
drivers, and a noise canceling electret microphone result in a comfortable headset providing
the ultimate in clear, understandable communications.
The Airman 850 headset with boom microphone is approved for aircraft use under FAA TSO’s
C57a and C58a.
2.2 Models covered
This manual only covers models listed here. Not all of the models listed here are currently
active and may not be available in the market. Bosch can, at its discretion, discontinue models
and part numbers.
Model
number
Description ANR Connector and wiring used
301317-000 Airman 850 Headset, Dual-
sided
Yes PJ-068 (or equivalent) & PJ-055 (or
equivalent)
Connector wiring diagram for catalog
numbers 301317-000; -003; -101; -200;
-201; -300; and -400, page 18
301317-002 Airman 850 Headset, Dual-
sided
Yes XLR
Connector wiring diagram for catalog
number 301317-002 (5-pin XLR), page
19
301317-003 Airman 850 Headset, Dual-
sided
Yes PJ-068 (or equivalent) & PJ-055 (or
equivalent)
Connector wiring diagram for catalog
numbers 301317-000; -003; -101; -200;
-201; -300; and -400, page 18
301317-101 Airman 850 Headset, Dual-
sided, customer specific
No PJ-068 & PJ-055
Connector wiring diagram for catalog
numbers 301317-000; -003; -101; -200;
-201; -300; and -400, page 18
301317-200 Airman 850 Headset, Single-
sided
No PJ-068 (or equivalent) & PJ-055 (or
equivalent)
Connector wiring diagram for catalog
numbers 301317-000; -003; -101; -200;
-201; -300; and -400, page 18
301317-201 Airman 850 Headset, Single-
sided, customer specific
No PJ-068 & PJ-055
Connector wiring diagram for catalog
numbers 301317-000; -003; -101; -200;
-201; -300; and -400, page 18

Airman 850 Description | en 7
Bosch Security Systems LLC Customer maintenance manual 09-2021 | V07 | F.01U.264.819
Model
number
Description ANR Connector and wiring used
301317-300 Airman 850 Headset, Single-
sided
Yes PJ-068 (or equivalent) & PJ-055 (or
equivalent)
Connector wiring diagram for catalog
numbers 301317-000; -003; -101; -200;
-201; -300; and -400, page 18
301317-400 Airman 850 Headset, Dual-
sided, customer specific
Yes PJ-068 (or equivalent) & PJ-055 (or
equivalent)
Connector wiring diagram for catalog
numbers 301317-000; -003; -101; -200;
-201; -300; and -400, page 18
Refer to
– Connector views / wiring diagrams, page 18

8en | Disassembly / Assembly Airman 850
09-2021 | V07 | F.01U.264.819 Customer maintenance manual Bosch Security Systems LLC
3 Disassembly / Assembly
3.1 Disassembly
The following procedure allows for complete disassembly of the Airman 850 final assembly.
i
Notice!
The removal process requires the steps to be followed in order. For example, to remove the
boom assembly, item 13, all steps before the Removing the Boom Assembly step must be
completed and in the listed order.
Assembly is the reversal of the disassembly procedure. Please take care when disassembling
to note details that may be required in the assembly process.
3.1.1 Remove cushions (Item 3)
To remove the cushions, do the following:
4At any point on the ear cup, gently pull the cushion from the faceplate.
3.1.2 Remove faceplate assembly (item 4)
To remove the faceplate assembly, do the following:
1. At the same time, push the two (2) catches located in the faceplate out of the way.
2. Rotate the faceplate assembly approximately 10° counterclockwise.
3. Carefully, pull the faceplate assembly away from the housing (item 6 or 7).
i
Notice!
Do not pull more than 12mm away from housing at this time.
4. Using a soldering iron, carefully disconnect the white and red wires from the speaker
solder terminals.
i
Notice!
Be careful not to touch plastic housing with soldering iron.
5. Remove the faceplate assembly.
3.1.3 Remove sleeve (item 8)
To remove the sleeve, do the following:
1. Carefully slide a small tweezers or pick under the sleeve.
i
Notice!
Avoid touching or scratching the circuit board, item 9 or 10.
2. Gently pry the sleeve up and away from the circuit board.
i
Notice!
If necessary, prying up the sleeve in several locations may be required to free the sleeve from
the housing (item 6 or 7), and the circuit board.

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Bosch Security Systems LLC Customer maintenance manual 09-2021 | V07 | F.01U.264.819
3. Once freed, carefully remove the sleeve from the housing.
3.1.4 Remove boom assembly / cover (item 13)
To remove the boom assembly/cover, do the following:
1. Insert a tweezers or small flat head screwdriver between the circuit board (item 9) and
the housing (item 6), gently pushing the cover away from the housing.
i
Notice!
It may be necessary to push around the housing in several locations to get the cover snaps to
free themselves from the housing.
2. Carefully desolder the four (4) cord unit wires from the circuit board (boom side only).
3. Gently pry the circuit board away from the cover being careful not to break the boom
wires hidden on the other side.
4. Remove the cover foam (item11).
5. Once the board is free from the cover, desolder the three (3) boom wires from the circuit
board(boom side only)
6. Remove the circuit board.
i
Notice!
The board is still attached to the overhead wires (dual-side versions only).
3.1.5 Removing the circuit board (item 9 or 10)
Follow the steps in Remove boom assembly / cover (item 13), page 9 .
4Disconnect the four overhead wires (dual-side versions only).
3.1.6 Removing the housing (item 6 or 7) or temple plate assembly (item 15 or
16) from the headband assembly (item 1)
4Push the housing off the glider assembly (item 2) through the slot in the top of the
housing.
i
Notice!
Care should be taken to not bend the headband assembly or housing during this process, as
it may take some force to do.
3.1.7 Removing the glider assemblies (item 2) and glider springs (item 18)
1. Bend the upper metal portion of the glider assembly straight.
2. Gently pull the glider assembly out of the headband assembly (item 1).
i
Notice!
The glider spring is located under the glider assembly and may spring out if the glider
assembly is removed too quickly.
3. Repeat steps 1 and 2 for other side of the headset.

10 en | Disassembly / Assembly Airman 850
09-2021 | V07 | F.01U.264.819 Customer maintenance manual Bosch Security Systems LLC
3.2 Assembly
i
Notice!
Assembly is a reversal of the disassembly procedure.
Steps need to be done exactly the reverse order of the disassembly procedure to ensure
proper headset fit and operation.
Please take care to properly align parts and wires to ensure proper operation.
See disassembly procedure, parts lists, assembly diagrams, and wiring diagrams for
reference.
17
1
2
3
3
4
4
6
8
7
8
9
10
11
11 12
13
14
5
18
21
22 23
24
25
26
25
22 23
26
Figure3.1: Airman 850 headset, dual sided, exploded view

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Bosch Security Systems LLC Customer maintenance manual 09-2021 | V07 | F.01U.264.819
17
1
3
2
4
5
6
8
9
11
13
14
15
16
18
24
25
26
22
23
Figure3.2: Airman 850 headset, single sided, exploded view

12 en | Disassembly / Assembly Airman 850
09-2021 | V07 | F.01U.264.819 Customer maintenance manual Bosch Security Systems LLC
Rotate
Assemble
Remove
Catch
(Push from other
side of faceplate
Catch
(Push from other
side of faceplate
10°
Figure3.3: Faceplate disassembly/assembly view

Airman 850 Parts list | en 13
Bosch Security Systems LLC Customer maintenance manual 09-2021 | V07 | F.01U.264.819
4 Parts list
4.1 General
When replacing parts, consult the illustrations in Assembly, page 10 and the parts lists.
Choose the parts corresponding to the catalog/model.
4.2 Airman 850, catalog number 301317-000; -002; -101; -200; -201;
-300; and -400
Model
Item CTN SAP number Description 000 002 003 101 200 201 300 400
1 64318095 F01U152147 Headband assembly 1
64318107 F01U152148 Headband assembly 1
64318117 F01U152149 Headband assembly 1
No longer available Headband assembly 1
S-F01U329356 F01U329356 Headband assembly 1
No longer available Headband assembly 1
S-F01U329357 F01U329357 Headband assembly 1
S-64318118 F01U216802 Headband assembly 1
2 800801000 F01U153681 Glider assembly 2 2 2 2 2 2 2 2
3 591486000 F01U151390 Cushion, ear, round, 1
piece
22221112
800456020 F01U118432 Ear cushion (2 per
package)
11111111
4 800939000 F01U153698 Faceplate/speaker
assembly
22221111
5 70413002 F01U152604 Cord
Approximate length: 5.5
ft (1.7 m)
1 1 1 1
702171000 F01U152574 Cord
Approximate length: 6.5
ft (2 m)
1
70413011 F01U152609 Cord
Approximate length: 5.5
ft (1.7 m)
1
No longer available Cord
Approximate length: 6.3
ft (1.9 m)
1 1
6 701613000 F01U110130 Housing, boom side 1 1 1 1 1 1 1 1
7 701612000 F01U110129 Housing non boom 1 1 1 1 1
8 S-701614000 F01U329353 Sleeve 1 piece 2 2 2 2 1 1 1 2

14 en | Parts list Airman 850
09-2021 | V07 | F.01U.264.819 Customer maintenance manual Bosch Security Systems LLC
S-701614000 F01U344779 2Sleeve 10 piece 1 1 1 1 1 1 1 1
9 S-F01U344779 F01U344779 PCB boom side 1 1
600704100 F01U157606 PCB boom side 1 1 1
S-F01U344780 F01U344780 PCB assembly 600 1
S-F01U344776 F01U344776 PCB assembly 600,
reduced x-talk
1
S-F01U344775 F01U344775 PCB assembly 300 1
10 S-F01U344777 F01U344777 PCBAAIRMAN 850 - non
boom side
1 1 1 1
No longer available PCBAAIRMAN 850 - non
boom side
11 591385000 F01U151370 Cover foam 2 2 2 2 1 1 1 2
12 701610000 F01U152470 Cover, non-boom side 1 1 1 1 1
13 800789000 F01U153679 Boom assembly 1 1 1 1 1
800789100 F01U153680 Boom assembly 1 1 1
141AIRMAN7-0900 F01U110451 Windscreen 2 pcs for
Airman 850, 7, 8, 8+
11111111
AIRMAN7-9050 F01U393945 50 pc windscreen bulk
Airman 850, 7, 8, 8+
11111111
AIRMAN7-9100 F01U393946 100 pc windscreen bulk
Airman 850, 7, 8, 8+
11111111
15 70531101 F01U152640 Temple pad not printed 1 1 1
16 70533000 F01U110213 Foam pad 1 1 1
17 590637000 F01U157438 Clothing clip 1 1 1 1 1 1 1 1
18 64305000 F01U110016 Glider spring 1 piece 2 2 2 2 2 2 2 2
S-F01U327240 F01U327240 2Glider spring 10 piece 1 1 1 1 1 1 1 1
19357893000 F01U157434 Zipper pouch 1 1
702126000 F01U152568 Carrying case 1 1 1 1 1 1
20 Not available from Bosch Resistor, 300Ω, 1/8W
5%
11111111
213,4 53731000 F01U109567 Overhead cordage 1 1 1 1 1
22 54857101 F01U150106 White wires from PCB
to speaker
22221112
23 54857103 F01U150110 Red wires from PCB to
speaker
22221112
245701246000 F01U152411 Boom rotator cap
256701664000 F01U152484 Acoustic cloth 2 2 2 2 1 1 1 2

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Bosch Security Systems LLC Customer maintenance manual 09-2021 | V07 | F.01U.264.819
263,7 S-F01U345383 F01U345383 ANR microphone 1 1 1 1 1 1 1 1
273,8 35398005 F01U146873 5-pin XLR connector
1. Either part number is acceptable.
2. This item has 10 pieces. Only one or two springs are needed per unit.
3. Not shown.
4. This item is part of the headband assembly (no.1) or can be purchased separately.
5. This item is part of Boom assembly (no. 13) or can be purchased separately.
6. Acoustic cloth is now included as part of no.3. Only one acoustic cloth can be used at a
time, either the spare part that needs to be attached to the faceplate (no. 4) or the cloth
that is included in the replacement ear cushion.
7. The ANR microphone is included with the PCBS and is sold separately.
8. This item is included in F01U152574 but is also sold separately.

16 en | Wiring diagrams Airman 850
09-2021 | V07 | F.01U.264.819 Customer maintenance manual Bosch Security Systems LLC
5 Wiring diagrams
5.1 Airman 850 wiring diagram (catalog numbers 301317-000; -002;
-003; -101; and -400)
Figure5.1: Top side, Airman 850, dual sided wiring diagram
Figure5.2: Bottom side, Airman 850 headset, dual sided wiring diagram

Airman 850 Wiring diagrams | en 17
Bosch Security Systems LLC Customer maintenance manual 09-2021 | V07 | F.01U.264.819
5.2 Airman 850 wiring diagram (catalog numbers 301317-200; -201;
and -300)
Figure5.3: Airman 850 headset, single sided wiring diagram

18 en | Wiring diagrams Airman 850
09-2021 | V07 | F.01U.264.819 Customer maintenance manual Bosch Security Systems LLC
5.3 Connector views / wiring diagrams
5.3.1 Connector view for catalog numbers 301317-000; -003; -200; -300; and -400
Figure5.4: Airman 850 headset, connector view (molded plugs)
5.3.2 Connector view for catalog numbers 301317-101; and -201
Figure5.5: Airman 850 headset, connector view (mechanical plugs)
5.3.3 Connector view for catalog number 301317-002
Figure5.6: Airman 850 headset, connector view (XLR plug)
5.3.4 Connector wiring diagram for catalog numbers 301317-000; -003; -101;
-200; -201; -300; and -400
PJ-068
(or equivalent)
PJ-055
(or equivalent)
Figure5.7: Airman 850 headset, connector wiring diagram

Airman 850 Wiring diagrams | en 19
Bosch Security Systems LLC Customer maintenance manual 09-2021 | V07 | F.01U.264.819
5.3.5 Connector wiring diagram for catalog number 301317-002 (5-pin XLR)
43
1
2
5
Pin 5 N/C
Pin 4 Black (shield)
Pin 3 Red
Pin 2 Yellow
Pin 1 White
Figure5.8: Airman 850 headset, 5-pin XLR wiring diagram

20 en | Maintenance Airman 850
09-2021 | V07 | F.01U.264.819 Customer maintenance manual Bosch Security Systems LLC
6 Maintenance
6.1 Microphone validation and adjustment
6.1.1 Microphone / amplifier sensitivity check
Headphone specifications are designed to comply with FAA TSO C57a, RCTA DO-214, and
DO-160D.
The headphone has two (2) operations:
– Passive- power is turned off.
– Active - power is turned on.
All modes tested, unless noted otherwise.
To test the sensitivity of the microphone, do the following:
1. Construct a test circuit. For more information, see illustration below.
2. Connect the test circuit to the microphone plug of the Device-Under-Test (DUT) headset.
For more information, see Connector views / wiring diagrams, page 18 .
i
Notice!
Verify correct polarity of connections
MIC +
MIC -
8 VDC
220
1/4W 5 %
+
470
1/2W 5 %
25 Vdc
V OUT CONNECT TO
MICROPHONE
PLUG
25
Figure6.1: Airman 850 headset boom microphone sensitivity check and adjustment test circuit
3. Calibrate a lab microphone, either self-contained (such as Larson Davis sound level
meter) or a separate measuring microphone with supporting equipment (such as Bruel
and Kjaer type 4192 with type 2669-B preamp).
4. Place the calibrated lab microphone 1/4 inch (6mm) in front of an artificial mouth (Bruel
and Kjaer type 4227, GRAS 44AB, etc.) or an equivalent speaker.
5. Connect a signal generator to the artificial mouth or the speaker.
6. Adjust for an output of 104dB SPL at 1 kHz @ 1/4 inch from the opening to the lab
microphone.
7. Remove the lab microphone.
8. Position the DUT headset microphone 1/4-inch (6mm) in front of the artificial mouth or
the speaker.
i
Notice!
The front acoustic port of the boom mic should be aligned with the center of the artificial
mouth or the speaker opening.
9. Measure the output of the headset microphone with a digital voltmeter.