TM-11-5805-387-20-2
TM
11-5805-387-20-2
TECHNICAL MANUAL
ORGANIZATIONAL
MAINTENANCE
MODEM RADIO TELETYPEWRITER
MD-522A/RC
(NSN 5815-00-919-4800)
HEADQUATERS, DEPARTMENT OF THE ARMY
5
APRIL
1984
TM 11-5805-387-20-2
SAFETY STEPS TO FOLLOW IF SOMEONE
IS THE VICTIM OF ELECTRICAL SHOCK
DO NOT TRY TO PULL OR GRAB THE lNDlVIDUAL
IF POSSIBLE, TURN OFF THE ELECTRICAL
POWER
IF YOU CANNOT TURN OFF THE ELECTRICAL
POWER, PULL, PUSH, OR LIFT THE PERSON TO
SAFETY USING A WOODEN POLE OR A ROPE
OR SOME OTHER INSULATING MATERIAL
SEND FOR HELP AS SOON AS POSSIBLE
AFTER THE INJURED PERSON IS FREE OF CONTACT WITH THE SOURCE OF ELECTRICAL
SHOCK, MOVE THE PERSON A SHORT
DISTANCE AWAY AND IMMEDIATELY START
ARTIFICIAL RESUSCITATION
A
TM 11-5805-387-20-2
WARNING
Be careful when working on this equipment. Serious injury or DEATH may result from contact
with these terminals.
DON’T TAKE CHANCES!
HIGH VOLTAGES EXIST IN THE FOLLOWING EQUIPMENT:
Various connectors and power supply components. . . . . . . . . . . . . . . . . . . . . .
DC LOOP NO. 1 and DC LOOP NO. 2 connectors . . . . . . . . . . . . . . . . . . . . . .
Loop battery module A5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Scope module A2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
27 vdc
120 vdc
127 vdc
1,100vdc
Set ON/OFF circuit breaker switch on front panel of MD-522A/GRC to OFF before removing
chassis to inspect this equipment.
WARNING
SAFETY PRECAUTION
A periodic review of safety precautions in TB 385-4, Safety Precautions for Maintenance of
Electrical/Electronic Equipment, is recommended. When the equipment is operated with covers
removed, do not touch exposed connections or components. Make certain you are not grounded
when making connections or adjusting components inside the test instruments.
WARNING
Adhesive/cement P/N EC-847 NSN 8040-00-691-6134 fumes are toxic. Avoid breathing fumes, and
avoid contact with skin. Provide adequate ventilation.
WARNING
Adequate ventilation should be provided while using TRICHLOROTRIFLUOROETHANE. Prolonged breathing of vapor should be avoided. The solvent should not be used near heat or open flame,
the products of decomposition are toxic and irritating. Since TRICHLOROTRIFLUOROETHANE
dissolves natural oils, prolonged contact with skin should be avoided. When necessary use gloves
which the solvent cannot penetrate. If the solvent is taken internally, consult a physician.
WARNING
Compressed air shall not be used for cleaning purposes except where reduced to less than 29 psi and
then only with effective chip guarding and personnel protective equipment. Do not use compressed
air to dry parts when TRICHLOROTRIFLUOROETHANE has been used. Compressed air is dangerous
and can cause serious bodily harm if protective means or methods are not observed to prevent chip or
particle (of whatever size) from being blown into the eyes or unbroken skin of the operator or other
personnel.
B
TM 11-5805-387-20-2
WARNING
RADIATION HAZARD
RADIOACTIVE MATERIAL
CONTROLLED DISPOSAL REQUIRED
ACCOUNTABILITY NOT REQUIRED
Meter . . . . . . . . Ra 226
. . . . . . . . . . . . 1.OuCi . . . . . . .
6625-00-257-1103
Radiation Hazard Information: The following radiation hazard information must
be read and understood by all personnel operating or repairing MODEM, MD522A/GRC. Hazardous radioactive materials are present in the above listed component of the MD-522A/GRC. The component is potentially hazardous when
broken. See qualified medical personnel and the local Radiological Protection
Officer (RPO) immediately if you are exposed to or cut by broken components.
First aid instructions are contained in TB 43-0116, TB 43-0122, and AR 385-11.
NEVER place radioactive components in your pocket. Use extreme care NOT to
break radioactive components while handling them.
NEVER remove radioactive components from cartons until you are ready to use
them.
If any of these components are broken, notify the local RPO immediately.
The RPO will survey the immediate area for radiological contamination and will
supervise the removal of broken components.
The above listed radioactive components will NOT be repaired or disassembled.
Disposal of broken, unserviceable, or unwanted radioactive components will be
accomplished in accordance with the instructions in AR 385-11.
C/D(blank)
*TM 11-5805-387-20-2
TECHNICAL MANUAL
HEADQUARTERS
DEPARTMENT OF THE ARMY
No. 11-5805-387-20-2
Washington, DC, 5 April 1984
ORGANIZATIONAL MAINTENANCE MANUAL
MODEM RADIO TELETYPEWRITER
MD-522A/GRC (NSN 5815-00-919-4800)
REPORTING OF ERRORS AND RECOMMENDING IMPROVEMENTS
You can help improve this manual. If you find any mistakes or if you
know of a way to improve the procedures, please let us know. Mail
your letter, DA Form 2028 (Recommended Changes to Publications
and Blank Forms), or DA Form 2028-2 located in back of this manual
direct to: Commander, US Army Communications-Electronics Command and Fort Monmouth, ATTN: DRSEL-ME-MP, Fort Monmouth,
New Jersey 07703. In either case, a reply will be furnished to you.
PAGE
CHAPTER 1
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1-1
Section I.
II.
III.
General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Equipment Description and Data... . . . . . . . . . . . . . . . . . . . . . . . . . . .
Technical Principles of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1-1
1-2
1-2
CHAPTER 2
MAINTENANCE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-0
Section I.
II.
III.
IV.
V.
VI.
APPENDIX A REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B MAINTENANCE ALLOCATION CHART (MAC) . . . . . . . . . . . . . . . . .
C EXPENDABLE SUPPLIES AND MATERIALS LIST. . . . . . . . . . . . . . .
GLOSSARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-1
2-1
2-7
2-13
2-20
2-26
A-1
B-3
C-1
G-1
I-1
*This manual supersedes the organizational maintenance portion of TM 11-5805-387 -15-1,6 June
1967, including all changes.
i
TM 11-5805-387-20-2
MODEM RADIO TELETYPEWRITER MD-522A/GRC
1-0
TM 11-5805-387-20-2
CHAPTER 1
INTRODUCTION
Section I. GENERAL INFORMATION
1-1. SCOPE
● Type of Manual: Organizational Maintenance
● Model Number and Equipment Name: Modem Radio Teletypewriter MD-522A/GRC
● Purpose of Equipment: Permits transmission and/or reception (transception) of teletypewriter
data and voice communications.
1-2. CONSOLIDATED INDEX OF ARMY PUBLICATIONS AND BLANK FORMS
Refer to the latest issue of DA PAM 310-1 to determine whether there are new editions, changes
or additional publications pertaining to the equipment.
1-3. MAINTENANCE FORMS, RECORDS, AND REPORTS
a. Reports of Maintenance and Unsatisfactory Equipment.
Department of the Army forms and procedures used for equipment maintenance will 1 be
those prescribed by DA Pam 738-750 as contained in Maintenance Management Update.
b. Report of Packaging and Handling Deficiencies.
Fill out and forward SF 364 (Report of Discrepancy (ROD)) as prescribed in AR 735-11-2/DLAR
4140.55/NAVMATINST 4355.73A/AFR 400-54/MCO 4430.3F.
c. Discrepancy in Shipment Report (DISREP) (SF 361).
Fill out and forward Discrepancy in Shipment Report (DISREP) (SF 361) as prescribed in AR 5538/NAVSUPINST 4610.33C/AFR 75-18/MCO P4610.19D/DLAR 4500.15.
1-4. DESTRUCTION OF ARMY ELECTRONICS MATERIEL
Destruction of Army electronics materiel to prevent enemy use shall be in accordance with
TM 750-244-2.
1-5. ADMINISTRATIVE STORAGE
Administrative Storage of Equipment issued to and used by Army activities will have preventive
maintenance performed in accordance with the PMCS charts (page 2-10) before storing. When removing
the equipment from administrative storage, the PMCS should be performed to assure operational readiness. Disassembly and repacking of equipment for shipment or limited storage are covered in chapter 2,
section VI of this manual.
1-6. REPORTING EQUIPMENT IMPROVEMENT RECOMMENDATIONS (EIR’S)
If your Modem Radio Teletypewriter MD-522A/GRC needs improvement, let us know. Send us an
EIR. You, the user, are the only one who can tell us what you don’t like about your equipment. Let us
know why you don’t like the design. Tell us why a procedure is hard to perform. Put it on an SF 368
(Quality Deficiency Report). Mail it to Commander, US Army Communications-Electronics Command
and Fort Monmouth, ATTN: DRSEL-ME-MP, Fort Monmouth, New Jersey 07703. We’ll send you a
reply.
1-1
TM 11-5805-387-20-2
1-7. NOMENCLATURE CROSS-REFERENCE
COMMON NAME
OFFICIAL NOMENCLATURE
Modem
Modem Radio Teletypewriter MD-522A/GRC
NOTE
Official nomenclature must be used when filling out report forms onlooking
up technical manuals.
Section II. EQUIPMENT DESCRIPTION AND DATA
1-8. EQUIPMENT CHARACTERISTICS, CAPABILITIES AND FEATURES
Refer to Operator’s Manual TM 11-5805-387-10-2.
1-9. LOCATION AND DESCRIPTION OF MAJOR COMPONENTS
Refer to Operator’s Manual TM 11-5805-387-10-2.
1-10. EQUIPMENT DATA
Refer to Operator’s Manual TM 11-5805-387-10-2.
1-11. SAFETY, CARE AND HANDLING
Observe all WARNINGS, CAUTIONS and NOTES in this manual. This equipment can be extremely
dangerous if these instructions are not followed.
Section III. TECHNICAL PRINCIPLES OF OPERATION
1-12. TECHNICAL PRINCIPLES OF OPERATION
When the modem is used as part of a radio teletypewriter system (fig. 1-1), its modulator section
accepts current pulses in a standard code from a sending teletypewriter and converts them into audio
tones; its demodulator section receives audio tones from an external source and changes them into
current pulses which operate a receiving teletypewriter. As part of a landline teletypewriter system
(fig. 1-2), the modem functions the same as described above. However, incoming and outgoing signals
can be received from, or applied to, telephone isolation amplifiers rather than radio equipment. As part
of a pony circuit setup (fig. 1-3), the modem provides teletypewriter communications between the local
receiving teletypewriter base and a remote (pony) teletypewriter.
NOTE
See TM 11-5805-367-34-2 for more extensive explanations on principle
of operation.
1-2
TM 11-5805-387-20-2
FIGURE 1-1. MODEM: TYPICAL CONFIGURATION FOR DUPLEX RADIO
TELETYPEWRITER SYSTEM
1 Teletypewriter [tty (SEND)] dc mark and space pulses are sensed by the modem.
2 The modem also senses voice signals from microphone.
3 Teletypewriter dc pulses are converted to tty tones and combined with voice signals by the modem.
4 These combined tty tones and voice signals are applied to a receiver-transmitter, and converted to
an rf signal.
5 This rf signal is then applied to an rf amplifier for transmission. The amplified rf signal is applied to
an antenna and sent to a distant station.
6 When received, rf signals are processed by an aux (auxiliary) receiver and applied to the modem.
The signals are separated and converted into voice signals and tty mark and space pulses.
7 The tty pulses are applied to a teletypewriter [tty (RCV)] and then applied to page printers or tape
punches for message interpretation.
8 An audio output can be applied to speaker for local use.
1-3
TM 11-5805-387-20-2
FIGURE 1-2. MODEM: TYPICAL CONFIGURATION FOR DUPLEX LANDLINE (600 OHMS)
TELETYPEWRITER SYSTEM
1 Teletypewriter [tty (SEND)] dc mark and space pulses are sensed by the modem.
2 Voice signals from the microphone are routed through the modem for switching purposes.
3 The modem converts the tty SEND mark and space pulses to tty tones.
4 These tones and voice signals are applied to an isolation amplifier, which provides impedance
matching for transmission over telephone lines to a distant station.
5 When received, an isolation amplifier again provides impedance matching. The received signals
are applied to the modem. The tty tones are converted into tty dc puIses.
6 The tty pulses are applied to a teletypewriter [tty (RCV)] and applied to page printers or tape
punches for message interpretation.
7 An audio output can be applied to a speaker for local use.
1-4
TM 11-5805-387-20-2
FIGURE 1-3. MODEM: TYPICAL CONFIGURATION FOR PONY OPERATION
1 Teletypewriter (local or remote send) dc mark and space pulses are sensed by the modem.
2 The modem converts tty dc pulses to tty tones for transmission.
3 With LOCAL-REMOTE switch on control panel (AN/GRC-142,-122) or switch assembly (AN/
GRC-142A, -142B, -122A, -122B) in REMOTE or LOCAL position, tty dc pulses are sent to [tty
(REMOTE)] on local receive circuits and applied to page printers or tape punches for message
interpretation.
4 Received tty tones are converted by the modem into dc mark and space pulses.
NOTE
When connected in the pony circuit configuration, the modem provides
local teletypewriter communications between the local receiving teletypewriter base and a remote (pony) teletypewriter located somewhere in the
nearby area of the base.
1-5
TM 11-5805-387-20-2
CHAPTER 2
MAINTENANCE INSTRUCTIONS
PAGE
Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mounting Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Preliminary Servicing and Adjustment:
Loop Current Internal-External Switch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Transmit NORM/REV Switch... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Preparation for Storage or Shipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
PMCS Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removing Chassis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Replacing
Chassis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Panel Gasket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Service upon Receipt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-0
2-22
2-3
2-1
2-3
2-6
2-7
2-25
2-10
2-20
2-24
2-23
2-1
2-13
2-1
TM 11-5805 -387-20-2
Section I. REPAIR PARTS, SPECIAL TOOLS AND SUPPORT EQUIPMENT
2-1. TOOLS AND TEST EQUIPMENT
Tools and test equipment required for organizational maintenance of the modem are listed in the
maintenance allocation chart (MAC) in appendix B of this manual.
2-2. SPECIAL TOOLS, TMDE AND SUPPORT EQUIPMENT
There are no special tools or TMDE required for organizational maintenance of this equipment.
Refer to Organizational Maintenance Repair Parts and Special Tools (RPSTL) manual TM,
TM 11-5805-387-20P-1.
Section II. SERVICE UPON RECEIPT
NOTE
Do not unpack modem until you unpack, assemble, install and connect the
rack in which it is to be placed.
2-3. UNPACKING THE MODEM
ITEM
REMARKS
ACTION
1. Carton
Open
2. M o d e m
Unpack
See figure 2-1.
Inspect for damage
done during shipment.
Report any damage on SF 364 Report of
Discrepancy (ROD).
Compare with packing
list.
Be sure shipment is complete. Report any
differences according to instructions in
DA PAM 738-750.
Check on front panel near nomenclature plate
for any modification work order (MWO)
numbers. They will appear only if the unit
has been used or reconditioned. Current
MWO’s which apply to the modem are listed
in DA Pam 310-1. Apply all URGENT
MWO’s. Schedule all NORMAL MWO’s.
Check for modifications.
2-4. INSTALLATION INSTRUCTIONS
CAUTION
Choose an installation space for the modem where adequate ventilation
is provided for transistor heat dissipation. Do not install unit close to other
heat-producing equipment, such as power units and space heaters. Excessive heat will damage the modem.
a. Tools, Test Equipment and Materials Needed for Installation
● All tools you will need to install the modem are in Tool Kit, Electronic Equipment
TK-101/G.
2-1
TM 11-5805-387-20-2
FIGURE 2-1.
2-2
UNPACKING MD-522A/GRC
TM 11-5805-387-20-2
b. Mounting Procedure
. The modem is designed to be used as part of a system, so determine correct installation
of the unit by its end use.
The modem may be installed on a separate mounting base.
. The modem may be stack-mounted with other units of similar case construction. For stackmounting installation, the modem is equipped with four round indentations.
c. Connections
CAUTION
Avoid transistor damage by always setting power switch to OFF before
making cable connections. Check polarity and measure voltage load of
power source before making connections. Transistors may be permanently
damaged by improper voltage or polarity.
Make all necessary external connections to modem at bottom of front panel as determined
by system requirements.
NOTE
No connection cables are supplied with modem; you must supply all cables
needed for specific connections. See figure 2-2 for detailed information
regarding connection of modem in typical equipment configurations.
2-3
TM 11-5805-387-20-2
J1
TO AUDIO OUTPUT
AT AUXILIARY RECEIVER
(SUCH AS RECEIVER-TRANSMITTER RT-662/GRC)
J2
TO TRANSMITTER AUDIO INPUT AT RADIO SET
(SUCH AS RADIO SET AN/GRC-106)
J3
TO HANDSET
(SUCH AS HANDSET H-33PT)
J4
TO LOCAL OR REMOTE LOUDSPEAKER
(SUCH AS DYNAMIC LOUDSPEAKER LS-166/U)
J5
TO LOCAL/REMOTE CONTROL
(SUCH AS CONTROL RADIO SET C-4846/GRA-74)
J6 and J7
TO TTY MACHINE
(SUCH AS TELETYPEWRITER TT-98/FG)
J8
TO NOMINAL 27V DC POWER SOURCE
FIGURE 2-2. CONNECTING MODEM TO TYPICAL EQUIPMENT (1 OF 2)
2-4
TM 11-5805-387-20-2
REF
DESIG
PIN
J1
A
FROM AUX RECEIVER AUDIO
B
J2
J3
CONNECTION
REF
DESIG PIN
CONNECTION
A
10 MW OUTPUT TO HEADPHONES
GROUND
B
GROUND
C
SPARE
c
50 OHM MICROPHONE INPUT
D
SPARE
D
SPARE
E
GROUND
E
GROUND
F
SPARE
F
RECEIVER-TRANSMITTER KEYLINE
G
SPARE
H
GROUND
H
GROUND
J
600 OHM AUDIO INPUT
J
SPARE
K
COMMON BUSS TO PIN K ON
K
SPARE
L
2-WATT OUTPUT TO SPEAKER
A
FROM RECEIVER-TRANSMITTER AUDIO
A
REMOTE ONE WAY-DUPLEX SWITCH
B
GROUND
B
GROUND
c
TO RECEIVER-TRANSMITTER
50 OHM MICROPHONE INPUT
c
AUX PRIMARY POWER SOURCE
(NOMINAL +27 VDC UNFUSED)
D
RECEIVER-TRANSMITTER KEYLINE
E
REMOTE SEND-RCV SWITCH
F
SPARE
G
SPARE
H
SPARE
J
SPARE
K
SPARE
A
DC LOOP NO. I POSITIVE SIDE
(INTERNAL SUPPLY )
GROUND
J4
J5
D
COMMON FOR PINS C AND J
E
GROUND
F
RECEIVER-TRANSMITTER KEYLINE
G
SPARE
H
GROUND
J
TO RECEIVER-TRANSMITTER
600 OHM INPUT
K
A
COMMON BUSS TO PIN K ON
J3 AND J4
10 MW OUTPUT TO HEADPHONES
B
GROUND
B
c
50 OHM MICROPHONE INPUT
c
D
SPARE
DC LOOP NO. I NEGATIVE SIDE
(INTERNAL SUPPLY )
E
MICROPHONE RETURN
A
DC LOOP NO. 2 POSITIVE SIDE
(INTERNAL SUPPLY)
F
RECEIVER-TRANSMITTER KEYLINE
B
GROUND
H
GROUND
c
J
600 OHM AUDIO INPUT
DC LOOP NO. 2 NEGATIVE SIDE
(INTERNAL SUPPLY)
K
COMMON BUSS TO PIN K ON
J2 AND J4
A
+27 VDC NOMINAL
B
+27 VDC NOMINAL
c
GROUND
D
GROUND
L
SPARE
J6
J7
J8
FIGURE 2-2. CONNECTING MODEM TYPICAL EQUIPMENT (2 OF 2)
2-5
TM 11-5805-387-20-2
d. Preliminary Servicing and Adjustment of Equipment
Make initial adjustments after installing modem but before beginning routine operation,
NOTE
The following adjustments can only be made with modem chassis removed
from its case (para 2-9).
e. Adjusting L oop Current Internal/External Switch
. Current for dc loop No. 1 and dc loop No. 2 may be supplied by internal loop battery module
A5 (see figure) or by external means.
CHASSIS INTERIOR, TOP VIEW
Internal/External switch A5S1 is a screwdriver adjustment on top of module A5 which sets the
appropriate sources of current for dc loops No. 1 and No. 2. See figure for settings provided.
A5S1 is normally set at LOOP 1 AND 2 INT when modem is shipped from the factory.
Set A5S1 according to desired sources of loop current for dc loops No. 1 and 2.
2-6
TM 11-5805-387-20-2
f. Adjusting Transmit Norm/Rev Switch
In most teletypewriter transmission and reception, lower frequency tone is used for mark
pulses and higher frequency tone for space puIses.
Transmit NORM/REV toggle switch
A3A1S1 located on board A3A1 of
transmitter module A3 (see figure)
permits modem to transmit markspace tones in reverse, if necessary.
SWITCH A3A1S1 (INSIDE)
CHASSIS INTERIOR,
TOP VIEW
Remove module dustcover as described in paragraph 2-9b.
Set NORM/REV switch according to type of transmission required.
Replace module dustcover.
Section III. PREVENTIVE MAINTENANCE CHECKS AND SERVICES (PMCS)
2-5. GENERAL
The following information is for QUARTERLY preventive maintenance checks and services (PMCS)
of modem. Quarterly PMCS shouId be performed every 90 calendar days of 8-hour-per-day operation.
Maintenance forms and records to be used and maintained on this equipment are specified in DA PAM
738-750. Perform all checks and services in sequence listed in table 2-1. If the equipment is
operated 16 hours, check at 45 day intervaIs.
NOTE
PMCS for the modem is limited to exterior and interior of chassis and case
and to exterior of modules ONLY.
a. Tools, Test Equipment and Material Needed for Organizational Level Maintenance
All tools you will need for maintenance on the modem are in Tool Kit, Electronic Equipment
TK 101/G (SC 5180-91-CL-R13).
Required test equipment: Multi meter AN/URM-105 (TM 11-6625-203-12).
Required material: Cement, 3M Co. ED-847
Cleaning compound
Cleaning cloth
Fine sandpaper
Soft-bristle brush
Dishwashing detergent
(item
(item
(item
(item
(item
(item
No.
No.
No.
No.
No.
No.
1,
2,
3,
4,
5,
6,
app.
app.
app.
app.
app.
app.
C)
C)
C)
C)
C)
C)
2-7
TM 11-5805-387-20-2
b. Routine Services
Routine services are a collection of checks and observations performed by the organizational
maintenance at all times, Routine services are not listed in the preventive maintenance checks and
services table, in order to separate the nonoperational from the operational services.
You should perform the following routines as necessary. Organizational maintenance personnel will
not be required to perform routine operator services or functions.
Check for cut or frayed cables
Check for rusting
Check for dented, bent, or broken
components
Check for loose nuts, bolts, and
connectors
Service the following items:
Chassis
Jacks
Modules
. Gaskets
If you find any damage during PMCS, refer to the troubleshooting table (table 2-2) or the
maintenance procedures in this manual for instructions on how to correct it. If the instructions are not there, notify your supervisor. A higher category of maintenance may be required.
NOTE
Use the number from the ITEM column of the PMCS table as the TM ITEM
No. for DA Form 2404 (Equipment Inspection and Maintenance Worksheet).
(See page 2-9).
2-8
TM 11-5805-387-20-2
DA FORM 2404, EQUIPMENT INSPECTION AND MAINTENANCE WORKSHEET.
2-9
TM 11-5805-387-20-2
TABLE 2-1. QUARTERLY PMCS TABLE
ITEM
NO.
ITEM
TO BE
INSPECTED
PROCEDURES
1
Operational
Check
Check the modem by operating it. (Refer to TM 11-5805-387-10-2.)
2
Front Panel
Meter
Be sure meter is showing correct indication for dc power input,
discriminator, dc loops or RCV setting, depending on operation.
3
Voice Signal
Perform the following check (Refer to voice transmission procedure
in TM 11-5805-387-10-2)
a. Put on headset.
b. Attach microphone at microphone connector.
c. Press and hold switch to key microphone and talk.
d. Note sidetone in headset.
2-10
TM 11-5805-387-20-2
TABLE 2-1. QUARTERLY PMCS TABLE - Continued
paragraph 2-11
2-11
TM 11-5805-387-20-2
TABLE 2-1. QUARTERLY PMCS TABLE - Continued
I
PROCEDURES
Check DA PAM 310-1 to determine if new applicable MWO’s have been
applied. All URGENT MWO’s must be applied immediately.
2-12
TM 11-5805-387-20-2
Section IV. TROUBLESHOOTING
2-6. GENERAL
Ž Troubleshooting at the organizational maintenance level requires you to locate any trouble
as quickly as possible.
●
Once trouble is located, repair or replace the part if you are authorized to do so or determine if a higher category of maintenance is required. Repairs by organizational maintenance are limited by tools, test equipment and replacement parts allocated to that level.
NOTE
Before using troubleshooting table (table 2-2), check your work order and
talk to the operator, if possible, for a description of symptoms if trouble
occurred while equipment was in operation.
Troubleshooting Table (Table 2-2)
●
Table 2-2 lists common problems that may occur during operation or maintenance of the
modem.
Ž Follow these steps to use table 2-2:
Ž Find the problem under MALFUNCTION.
Ž Check for possible causes of the problem under TEST OR INSPECTION.
●
●
Use the procedures under CORRECTIVE ACTION to correct the problem.
This manual cannot list all trouble that may occur, nor everything to check nor all possible
procedures to correct troubles listed. If trouble is not listed in table 2-2 or is not corrected
by the procedures under CORRECTIVE ACTION, notify your supervisor.
WARNING
Dangerous voltages exist in this equipment. For some of the following
procedures, you must remove the modem chassis from its case. Set ON/OF F
circuit breaker switch on front of panel to OFF before removing chassis,
then follow instructions in paragraph 2-9 for removal.
2-13
TM 11-5805-387-20-2
Table 2-2 TROUBLESHOOTING
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
1. No +20 volt dc indication on front panel meter
Step 1. See if circuit breaker is tripped.
CAUTION
To prevent damage to the equipment, do not hold ON/OFF circuit breaker
switch on front panel in ON position.
Reset circuit breaker switch to ON.
If it trips again, higher category maintenance required.
Step 2. Use Multimeter AN/URM-105 to check for 28 volts dc between pins A (+) and C (–)
of POWER input cable.
Turn circuit breaker ON/OFF switch to OFF.
Disconnect POWER cable from primary
power connector.
~
Connect multimeter as shown in figure.
POWER
CABLE
If 28 volts dc is absent, replace POWER cable.
If 28 volts dc is present, go to 2.
MULTIMETER
AN/URM-105
2. No +20 volt dc indication on front panel meter but primary power input normal
Step 1. Be sure modules are securely seated in their sockets.
CHASSIS INTERIOR, TOP VIEW
Securely seat all modules in their sockets.
2-14
TM 11-5805-387-20-2
Table 2-2 TROUBLESHOOTING - Continued
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Step 2. Use Multimeter AN/URM-105 to check switches S3 and S4 for bad contacts.
If contacts are bad or there is not +20 volt dc indication on meter after
reconnecting POWER cable, higher category of maintenance required.
3. No indication on front panel meter with METER FUNCTION switch at RCV LEVEL
Step 1. Check for loose or damaged RCVR TRANS AUDIO or AUX RCVR AUDIO cables.
Be sure the associated receiver is working properly and the appropriate
connectors are clean and fit tightly.
Step 2. Use Multimeter AN/URM-105 to check switches S3 and S1 for bad contacts.
If contacts are bad, higher category of maintenance required.
2-15
TM 11-5805-387-20-2
Table 2-2 TROUBLESHOOTING - Continued
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Step 3. Be sure receiver audio module A1 is securely seated in a corrosion-free socket.
Remove module A1 from its socket and visually check for any rust or corrosion.
Remove corrosion by lightly sanding with fine sandpaper. Securely seat module
A1 back in its socket.
4. Incorrect meter function with METER FUNCTION switch at DISCRIMINATOR
Be sure receiver module A4 is securely seated in a corrosion-free socket.
Remove module A4 from its socket and visually check for any rust or corrosion.
Remove corrosion by lightly sanding with fine sandpaper. Securely seat module
A4 back in its socket.
2-16
TM 11-5805-387-20-2
Table 2-2 TROUBLESHOOTING - Continued
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
5. No indication on front panel meter of loop current in dc loops No. 1 and No. 2.
Step 1. Check for loose or damaged dc loop No. 1 or dc loop No. 2 cables.
Be sure that the appropriate connector is clean and fits tightly. If cables are
shorted or have open conductors, replace them.
Step 2. Use Multimeter AN/URM-105 to check switch S3 for bad contacts. (See malfunction 2
for location of switch S3.)
If contacts are bad, higher category of maintenance required.
Step 3. Be sure loop battery module A5 is securely seated in a corrosion-free socket.
CHASSIS INTERIOR, TOP VIEW
Step 4. Use Multimeter AN/UM-105 to check switch S2 for bad contacts.
If contacts are bad, higher category of maintenance required.
2-17
TM 11-5805-387-20-2
Table 2-2 TROUBLESHOOTING – Continued
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
6. Scope display malfunction. (See figures for scope traces for properly tuned associated radio
receivers).
Be sure scope module A2 is securely seated in a corrosion-free socket.
CHASSIS INTERIOR, TOP VIEW
Remove module A2 (para 2-9c) from its socket and visually check for any rust or
corrosion. Remove corrosion by lightly sanding with fine sandpaper. Securely
seat module A2 back in its socket.
2-18
TM 11-5805-387-20-2
Table 2-2 TROUBLESHOOTING - Continued
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
7. No voice reception
Step 1. Be sure receiver module A4 is securely seated in a corrosion-free socket.
See malfunction 4.
Step 2. Check for loose or damaged SPEAKER + REMOTE or MICROPHONE cables.
Be sure that associated connectors are clean and fit tightly. If cables are shorted
or have open conductors, replace them.
Step 3. Use Multimeter AN/URM-105 to check switch S4E for bad contacts. (See
malfunction 2 for location of S4.)
If contacts are bad, higher category of maintenance required.
8. No voice transmission; teletypewriter (tty) normal
Step 1. Check for loose or damaged AUXILIARY, SPEAKER + REMOTE or MICROPHONE
cables.
Be sure that associated connectors are clean and fit tightly. If cables are shorted
or have open conductors, replace them.
Step 2. Use Muitimeter AN/URM-105 to check switch S4B or S4C for bad contacts. (See
malfunction 2 for location of S4.)
If contacts are bad, higher category of maintenance required.
9. No tty transmission; voice normal
Use Multimeter AN/URM-105 to check switch S4D for bad contacts. (See malfunction 2
for location of S4.)
If contacts are bad, higher category of maintenance required.
10. No tty or voice transmission
Be sure transistor module A3 is securely seated in a corrosion-free socket.
CHASSIS INTERIOR, TOP VIEW
Remove module A3 from its socket and visually check for any rust or corrosion.
Remove corrosion by lightly sanding with fine sandpaper. Securely seat module
A3 back in its socket.
2-19
TM 11-5805-387-20-2
Section V. MAINTENANCE PROCEDURES
2-7. GENERAL
Organizational maintenance of the modem is limited t o :
1. INSPECTION
Interior of modem and exterior of modules.
2. REMOVAL
Modem chassis from case.
Module dust covers.
Modules.
3. CLEANING
Exterior and interior of modem case and chassis and exterior of modules,
4. REPAIRS AND REPLACEMENTS
Front panel gasket.
Module dust covers.
Modules.
Modem chassis into case.
5. TESTING
Front panel assembly.
6. PAINTING
Metal surfaces.
7. ADJUSTMENTS
All controls on exterior of modem.
2-8. INSPECTION AND SERVICE
Inspect and service interior of modem case and exterior of modules. Do not remove module covers.
Check for dirt, dust, or moisture; check for loose screws or nuts. Check for loose or broken control
knobs and shorted or open connector contacts.
2-9. REMOVAL
a. Modem Chassis from Case
Follow procedure given below:
WARNING
To prevent dangerous shocks, set ON/OFF circuit breaker switch on front
panel of modem to OFF before removing chassis.
2-20
TM 11-5805-387-20-2
Disconnect and label all external cables from front panel connectors.
Loosen six captive screws around outside edge of front panel.
WARNING
Be careful when pulling modem chassis from case; it weighs 36 pounds.
Grasp raised ribbed frame
around outside edge of front
panel. Gently pull modem
chassis out of case.
2-21
TM 11-5805-387-20-2
b. Module Dust Cover
Lift up bail handles and turn them to the left until they release. Lift off cover.
For scope module A2, remove four screws from cover and lift it off.
c. Modules
Remove screw, Iockwasher, washer and spring from each corner of module.
Pull up on module (or bail handle if cover has not been removed) to unplug module from
chassis connector.
2-10. CLEANING
Clean exterior and interior of modem chassis and case and exterior of modules only. Do not
remove moduIe covers.
CAUTION
Do not press on meter or scope face when cleaning.
Remove dust and loose dirt from outside surfaces of the modem with a clean, soft cloth
(item 3, app. C). Cloth may be dampened with water, and mild soap (item 6, app. C) may
be used for better cleaning.
WARNING
See trichlorotrifluoroethane warning on page a.
WARNING
See compressed air warning on page a.
Remove grease, fungus and ground-in dirt from case. Use a cloth dampened (not wet) with
cleaning compound (item 2, app. C).
Remove dust or dirt from plugs and jacks with a brush (item 5, app. C).
2-22
TM 11-5805-387-20-2
2-11. REMOVAL AND REPLACEMENTS
a. Front Panel Gasket
Replace front panel gasket on modem if it is cracked, broken, frayed, worn, or out of its groove
and flattened. Follow this procedure:
Follow instructions given in paragraph 2-9 for removing modem from case. Pull chassis out
only far enough to loosen front panel gasket.
WARNING
See trichlorotrifluoroethane warning on page a.
WARNING
See compressed air warning on page a.
Remove all cement and dirt from groove in which gasket is seated. Use a cloth dampened
(not wet) with cleaning compound (item 2, app. C).
Spread thin film of EC-847 cement (item 1, app. C) in groove.
Place new gasket in groove. Gently press to insure complete bonding.
NOTE
Let cement dry for at least 1 hour before placing chassis back into case, so
the gasket won’t stick to the chassis.
Follow instructions in paragraph below to replace chassis into case after replacing front panel
gasket.
b. Module Dust Covers
Place dust cover over module. Turn bail handles to the right until they are tight.
For scope module A2, place cover over module and tighten four screws to hold cover in place.
c. Modules
Plug module into appropriate chassis connector.
Secure modules to chassis by tightening screws with springs, lock washers and washers in
each corner of module.
2-23
TM 11-5805-387-20-2
d. Replacing Modem Chassis into Case
Follow procedure given below:
Be sure modem case is top side up. (Four depressions on top of case.)
Grasp chassis by raised ribbed frame (not components); begin sliding chassis into case. When
about 1 inch of chassis remains outside case, maneuver chassis until it engages guide prongs
at back of case. Slide chassis into case.
Alternately tighten six captive holddown screws around outside edge of front panel.
Reconnect any cables that may have been removed. Remove temporary cable labels. Be
sure all cables fit tightly in their correct sockets.
Tighten six screws.
2-12. TESTING
Locate faulty components mounted on front panel and check for shorts at the power connector.
2-13. PAINTING
Remove rust and corrosion from metal surfaces by lightly sanding with fine sandpaper (item 4,
app. C). Brush two thin coats of the proper paint on bare metal to protect it from further corrosion.
Refer to applicable procedures in TB 43-0118.
2-14. ADJUSTMENT
Check front panel controls to be sure that they operate freely.
2-24
TM 11-5805-387-20-2
Section VI. PREPARATION FOR STORAGE OR SHIPMENT
2-15. SECURITY PROCEDURES
Refer to AR 190-11 or AR 190-13.
2-16. DISASSEMBLY OF EQUIPMENT
Use the procedures below when placing the modem in storage or moving it to a different
location.
a. Disconnecting Cables
Set modem circuit breaker switch to OFF.
Disconnect power cable from PRIMARY POWER
2-25
TM 11-5805-387-20-2
Disconnect all cables attached to front panel connectors. Replace dust caps on connectors.
Close hinged cover at upper left front panel. Secure it by turning the thumbscrew to
the right.
b. Component Disassembly
If the modem is installed on a mounting base, such as MT-3140/GRC-106, pull release
handles on the base towards you while turning them towards the outside of the unit.
Lift the modem off of the mounting base.
2-17. REPACKING FOR SHIPMENT
If the modem is to be moved over a short distance for immediate reuse, put it in a
corrugated or wooden box and place padding over the control panel. Use rags or
crumpled paper for padding.
2-26
TM 11-5805-387-20-2
NOTE
Do not stack other equipment on top of modem.
2-18. REPACKING FOR STORAGE
If modem is to be stored for longer than two weeks or is to be shipped for use by other
personnel or activities, return it to its original shipping container (fig. 2-1).
Fold a piece of corrugated cardboard (W5c, B-flute) to form a spring (shock) pad for
bottom of carton. Set the spring pad in the carton.
Place the modem in the carton.
Fold sheets of corrugated cardboard to form spring pads for the front, rear and sides
of the modem; set them in place.
Slide a sheet of corrugated (A/B) doublewall cardboard between the front spring pad
and the carton wall.
Fold a sheet of corrugated cardboard to form a spring pad for the top of the modem.
Set it in place.
Close the carton cover and secure the edges with water resistant tape (PPP-T-76,
3-inch).
Place all TM’s in a barrier bag and tape the bag closed.
2-19. TYPES OF STORAGE
Short term (administrative) = 1 to 45 days. All equipment in administrative storage
must be able to be made ready within 24 hours for use on a mission. Before placing
any item in administrative storage, perform the next scheduled PMCS and correct or
repair any deficiencies you find. The administrative storage site should provide required protection from extreme weather conditions and allow you to reach the equipment for visual inspections or exercises when applicable.
Intermediate = 46 to 180 days.
Long term or flyable = no time limit.
2-27/(2-28 blank)
TM 11-5805-387-20-1
APPENDIX A
REFERENCES
A-1. INTRODUCTION
The Consolidated Index of Army Publications and Blank Forms, DA PAM 310-1, should be consulted frequently for revisions and new publications that pertain to this manual. The following is a
list of all forms, technical bulletins and technical manuals referenced in this manual.
A-2. FORMS
DA Form 2028 . . . . . . . . . . . . . . . . . .
DA Form 2404 . . . . . . . . . . .. . . . . . . . . . . . . .
SF Form 361. . . . . . . . . . . . . . . . . . . .
SF Form 364 . . . . . . . . . . . . . . . . . . . .
SF Form 368 . . . . . . . . . . . . . . . . . . . .
Recommended Changes to Publications and Blank Forms
Equipment Inspection and Maintenance Worksheet
Discrepancy in Shipment Report
Report of Discrepancy (ROD)
Quality Deficiency Report
A-3. TECHNICAL BULLETINS
TB43-0116. . . . . . . . . . . . . . . . . . . . . Identifications of Radioactive Items in the Army Supply
System
TB43-0118 . . . . . . . . . . . . . . . . . . . . . Field Instructions for Painting and Preserving Electronics
Command Equipment Including Camouflage Pattern
Painting of Electronic Shelter
TB43-0122 . . . . . . . . . . . . . . . . . . . . . Instructions for the Safe Handling and Identification of US
Army Communication-Electronics Command Managed
Radioactive Items in the US Army Supply System
A-4. TECHNICAL MANUALS
TM11-5805-387-10-1 . . . . . . . . . . . . . Operator’s Manual: Modem Radio Teletypewriter
MD-522/GR
TM 11-5805-387-20P-2. . . . . . . . . . . . Organizational Repair Parts List: Modem Radio Teletypewriter MD-522/GRC
TM 11-5805-387-24P-1 . . . . . . . . . . . . Organizational, Direct Support, and General Support
Maintenance Repair Parts and Special Tools Lists
(Including Depot Maintenance Repair Parts and Special
Tools) for Modem Radio Teletypewriter MD-522/GRC
(NSN 581 5-00-919-4800)
Direct
Support and General Support Maintenance: Modem
TM 11-5805-387-34-2 . . . . . . . . . . . . .
Radio Teletypewriter MD-522A/GRC
TM 11-6625-203-12 . . . . . . . . . . . . . . Operator’s and Organizational Maintenance Manual: Multimeter AN/URM-105 Including Multimeter ME-77/U
A-1
TM 11-5806-387-20-1
TM740-90-1 . . . . . . . . . . . . . . . . . . . . Administrative Storage of Equipment
TM750-244-2 . . . . . . . . . . . . . . . . . . . Procedures for Destruction of Electronic MaterieI to Prevent
Enemy Use (Electronics Command)
A-5. MISCELLANEOUS PUBLICATIONS
AR 190-11 . . . . . .. . . . . . . . . . . . . . . . . . . Physical Security of Arms, Ammunition, and Excplosives
AR 190-13 . . . . . . . . . . . . . . . . . . . . . The Army Physical Security Program
AR 385-11 . . . . . . . . . . . . . . . . . . . . Ionizing Radiation Protection (Licensing, Control, Transportation, Disposal, and Radiation Safety)
DA PAM310-1 . . . . . . . . . . . . . . . . . Consolidated Index of Army Publications and Blank Forms
. . . . . . . . . . . . The Army Maintenance Management System (TAMMS)
DA PAM 738-750
SC-5180-91-CL-R . . . . . . . . . . . . . . . . . . . . S e t s , K i t s a n d O u t f i t s , C o m p o n e n t L i s t : T o o l
Kit,
Electronics
Equipment,
TK101/G
A-2
TM 11-5805-387-20-2
APPENDIX B
MAINTENANCE ALLOCATION
Section I. INTRODUCTION
B-1. GENERAL
This appendix provides a summary of maintenance operations for MD-522A/GRC. It authorizes
categories of maintenance for specific maintenance functions on repairable items and components, as well as tools and equipment needed to perform each function. Use this appendix as
an aid in planning maintenance operations.
B-2. MAINTENANCE FUNCTION
Maintenance functions will be limited to and defined as foliows:
a. INSPECT. To visually examine an item and compare its physical, mechanical and/or electrical
characteristics with established standards in order to determine its serviceability.
b. TEST. To measure mechanical or electrical characteristics of an item and compare those
characteristics with prescribed standards in order to verify serviceability.
c. SERVICE. Procedures required periodically to keep an item in proper operating condition,
e.g., to clean (decontaminate), preserve, drain, paint, or to fill up fuel, lubrication, hydraulic
fluid, or compressed air supplies.
d. ADJUST. To set operating characteristics to the specified parameters and keep them within
their prescribed limits.
e. ALIGN. To adjust specified variable elements of an item to bring about the best or desired
performance.
f. CALIBRATE. To correct test measuring and diagnostic equipment used in precision
measurements. Must compare two instruments, one of which is a certified standard of
known accuracy, to detect and adjust any differences in the accuracy of the instrument being compared.
g. INSTALL. To place, seat or fix into position an item, part or module (component or assembly)
to allow proper functioning of equipment or system.
h. REPLACE. To substitute a functioning like type part, subassembly or module (component or
assembly) for its unserviceable counterpart.
i. REPAIR. To correct specific damage, fault, malfunction or failure in a part, subassembly,
module (component or assembly), end item or system by applying maintenance services (a-f,
h above) or other maintenance actions (welding, grinding, riveting, straightening, facing,
remachining or resurfacing). This function does not include trial and error replacement of
such items as fuses, lamps or electron tubes.
j. OVERHAUL. The highest degree of maintenance applied to Army equipment. This function
does not normally return an item to "like new" condition but restores it to completely serviceable/operational conditions according to maintenance standards (i.e., DMWR) in appropriate technical publications.
k. REBUILD. The highest degree of materiel maintenance applied to Army equipment. To restore
unserviceable equipment to a "like new" condition according to original manufacturing standards. This function includes returning to zero those age measurements (hours, miles, etc.)
considered in classifying Army equipment/components.
B-1
TM 11-5805-387-20-2
B-3. COLUMN ENTRIES
a. COLUMN 1: GROUP NUMBER. Identifies components, assemblies, subassemblies and modules
with next higher assembly.
b. COLUMN 2: COMPONENT/ASSEMBLY. Lists the noun names of components, assemblies,
subassemblies and modules for which maintenance is authorized.
c. COLUMN 3: MAINTENANCE FUNCTIONS. Lists functions to be performed on item listed in Column 2. When items are listed without maintenance functions, it is only to have group
numbers in MAC and RPSTL coincide.
d. COLUMN 4: MAINTENANCE CATEGORY. Lists a “work time” figure in the appropriate subcolumn(s) to show the lowest level of maintenance authorized to perform the function listed
in Column 3. If number or complexity of tasks within limited maintenance function varies at
different maintenance categories, appropriate “work time” figures will be shown for each
category. Task-hours specified by “work time” figures represent the average time needed to
restore a subassembly, module (component or assembly), end item or system to serviceable
conditions under typical field operating conditions. The “work time” figure includes preparation time, troubleshooting time and quality assurance/quality control time as well as time required to perform specific tasks identified for maintenance functions authorized in the
maintenance allocation chart (MAC). Subcolumns of Column 4 are as follows:
C
O
F
H
D
- Operator/Crew
- Organizational
- Direct Support
- General Support
- Depot
e. COLUMN 5: TOOLS AND EQUIPMENT. Specifies by code those common tool sets (not individual tools) and special tools, test and support equipment needed to perform the
designated function.
f. COLUMN 6: REMARKS. Contains an alphabetic code leading to the appropriate remark in B-5
(below) for the item opposite each code.
B-4. TOOLS AND TEST EQUIPMENT REQUIREMENTS
a. TOOL OR TEST EQUIPMENT REFERENCE CODE. Numbers in this column coincide with
numbers used in Column 5 of the MAC and indicate applicable tool or test equipment for
maintenance functions.
b. MAINTENANCE CATEGORY. Codes in this column indicate maintenance category allocated
the tool or test equipment.
c. NOMENCLATURE. Lists noun name and nomenclature of tools and test equipment needed to
perform maintenance functions.
d. NATIONAL/NATO STOCK NUMBER. Lists NATIONAL/NATO stock number of specified tool or
test equipment.
e. TOOL NUMBER. Lists manufacturer’s part number of tool, followed by (5 digit) Federal Supply
Code for Manufacturers in parentheses.
B-5. REMARKS
a. REFERENCE CODE. Refers to appropriate item in Section II, Column 6.
b. REMARKS. Provides necessary information to explain items appearing in Section II.
B-2
Section II.
TM 11-5805-387-20-2
B-3
TM 11-5805-387-20-2
B-4
TM 11-5805-387-20-2
B-5
TM 11-5805-387-20-2
B-6
TM 11-5805-387-20-2
B-7
TM 11-5805-387-20-2
B-8
TM 11-5805-387-20-2
B-9
TM 11-5805-387-20-2
B-10
TM 11-5805-387-20-2
B-11
TM 11-5805-387-20-2
B-12
Section III.
Section III.
TM 11-5805-387-20-2
B-13
Section IV.
TM 11-5805-387-20-2
B-14
Section IV.
TM 11-5805-387-20-2
page B-15/(B-16 blank
TM 11-5805-387-20-2
APPENDIX C
EXPENDABLE SUPPLIES AND MATERIALS LIST
Section I. INTRODUCTION
C-1 .
GENERAL INFORMATION
This appendix lists expendable supplies and materials you will need to operate and maintain
MD-522A/GRC. These items are authorized to you by CTA 50-970, Expendable Items.
C-2.
EXPLANATION OF COLUMNS
a. ITEM NO. This number is referenced in the narrative instructions to identify the material (for
example, “Use cleaning compound, Item 9, App. C”).
b. LEVEL. Shows the lowest level of maintenance that needs the listed item. Enter as applicable:
C - Crew/Operator
O - Organizational Maintenance
c. NATIONAL STOCK NUMBER. Shows the National Stock Number assigned to each item and
used to requisition that item.
d. DESCRIPTION. Shows the National Item Name and (if required) a short description to identify
and locate the item. The last line for each item shows the Federal Supply Code for Manufacturers (FSCM) in parentheses, followed by the part number.
e. UNIT OF MEASURE (U/M). Shows the measure of the item needed to perform the actual operational/maintenance function. This measure is shown by a two-letter abbreviation (for example,
EA, OZ, IN).
EXPENDABLE SUPPLIES AND MATERIALS LIST
ITEM
NO.
LEVEL
1
2
3
4
5
6
0
0
0
0
0
0
NATIONAL
STOCK
NUMBER
8040-00-691-6134
6850-00-105-3084
8305-00-267-3015
7920-00-178-8315
7930-01-055-6121
DESCRIPTION
U/M
Cement, 3M Co. EC-847 (76381)
Cleaning compound
Cloth, cheese cloth (81348)
Sandpaper, No. 0000
2 3/4" long bristle brush
Detergent, GP, Liq
OZ
OZ
YD
SH
EA
GL
C-1/(C-2 blank)
TM 11-5805-387-20-2
GLOSSARY
audio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Frequencies that are heard.
auxiliary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Any item not directly a part of a specific
component or system but required for its
functional operation.
chassis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The metal framework on which the parts of
the modem are mounted.
coarse tune . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . To tune the signal within a "ballpark" range
for fine tuning.
demodulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A device used to convert audio tones into dc
mark and space pulses.
dc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Electric current (waves) that flows in only
one direction and remains essentially
constant in magnitude.
intensity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A term used to designate brightness or
luminance of the spot.
modulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A device used to convert direct current (dc)
mark and space pulses into audio tones.
polarity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Having two opposite charges - one positive,
one negative.
pony loop circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . Allows teletypewriter order wire transmission
and reception over landlines from a remote
station when system is not operating in the
duplex mode.
remote . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Control indirectly or from a distance.
single channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Use of one frequency for transmission and
reception.
stabilize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . To hold steady.
Glossary-1/Glossary-2 blank
TM 11-5805-387-20-2
INDEX
SUBJECT
PAGE
A
Adjustment
Adjustments, preliminary:
Loop current internal - external
switch
Transmit NORM/REV switch
2-6
2-6
2-6
2-7
2-20
2-24
2-1
2-22
1-1
2-3
1-1
1-2
2-6
2-6
1-1
1-2
F
1-1
2-23
Forms, records, reports
Front panel gasket
G
Gasket, front panel:
Replacement procedure
1-1
1-2
2-6
2-6
Major components, location of
Materials, tools, test equipment:
for Installation
for PMCS
Module:
A3, transmitter
A5, loop battery
Modules, removal and replacement
Mounting procedure
1-2
2-1
2-7
2-7
2-6
2-22
2-3
N
E
Equipment data and description
Lists, components
Location of major components
Loop:
Battery module A5
Internal - external switch
M
D
Data and description, equipment
DC:
Loop no. 1
Loop no. 2
Destruction of Army materiel
PAGE
L
C
Chassis, main:
Removal
Replacement
Checking unpacked equipment
Cleaning
Components, list
Connections
Cross-reference list, nomenclature
SUBJECT
2-23
Nomenclature cross-reference list
1-1
P
Painting
Preliminary servicing and adjustment
Preparing for storage and shipment
Preventive maintenance checks and
services (PMCS)
Table
Principles of operation, technical
Purpose of equipment
2-24
2-6
2-25
2-7
2-10
1-2
1-1
R
Records, reports, forms
Removal:
Main chassis from case
Modules
Reports, forms, records
1-1
2-20
2-22
1-1
I
S
Installation:
Tools required
Inspection and service
Internal-external switch adjustment
2-1
2-20
2-6
Scope
Switch:
Loop current internal - external
Transmit NORM/REV
1-1
2-6
2-7
INDEX - 1
TM 11-5805-387-20-2
INDEX
- continued
PAGE
Subject
T
Table:
PMCS
Troubleshooting
Technical principles of operation
Testing
Tools, test equipment, materials:
for Installation
for PMCS
Transmit NORM/REV switch
adjustment
Transmitter:
Module A3
Troubleshooting:
Table
2-7
2-13
1-2
2-24
2-1
2-7
2-7
2-7
2-13
U
Unpacking
INDEX-2
2-1
TM-11-5805-387-20-2
By Order of the Secretary of the Army:
JOHN A. WICKHAM JR.
General, United States Army
Chief of Staff
Official:
ROBERT M. JOYCE
Major General, United States Army
The Adjutant General
DISTRIBUTION:
To be distributed in accordance with DA FORM 12-51 requirements
for MD-522/GRC.
U.
S.
GOVERNMENT
PRINTING
OFFICE
;
1990
0
-
261-872
(20604)
PIN : 055261-000
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