GENERAL SUPPORT MAINTENANCE INSTRUCTIONS
Section I. GENERAL
ments are given in the troubleshooting/maintenance
instructions in TM 11-5825-271-12.
a. This chapter contains the general support
b. Appropriate waveforms are shown on the
maintenance instructions for the NDB transmitter and the
ATU. There is no general support maintenance for the
waveforms are provided as a reference and are not
required for general support maintenance tasks.
b. General support maintenance for the NDB
transmitter and ATU comprises removal and
4-3. Tools and Test Equipment
replacement of authorized assemblies, subassemblies
Tools and test equipment required for general support
and certain chassis-mounted components. Procedures
maintenance tasks are listed in TM 11-5825-271-12.
are included in this chapter to make sure that repair has
been successfully accomplished.
Maintenance procedures, including troubleshooting
instructions, for general support maintenance are
identical to those authorized at the organizational
a. Overall voltage or resistance checks are not
maintenance level; refer to TM 11-5825-271-12.
applicable to the maintenance of the NDB transmitter
and ATU. Pertinent resistance and voltage measure-
Section II. GENERAL SUPPORT MAINTENANCE OF NDB TRANSMITTER
(2) Remove two screws (3), lockwashers (4),
and flat washers (5) securing the power probe assembly
a. This section provides instructions for performing
A1A6 (6). Remove the power probe assembly A1A6 by
the maintenance functions allocated to general support
pulling it up out of connector XA6 (15). Retain power
maintenance on the NDB transmitter.
probe assembly A1A6 and the attaching hardware for
b. Support illustrations are provided to aid in the
performance of procedures.
The numbers in
(3) Remove two screws (14), nuts (7), lock-
parentheses referenced in the text, e.g., (1), (2), etc,
washers (8), and flat washers (9) securing connector
correspond to the item callout on the illustration.
XA6 (15) to the mounting bracket. Identify the attaching
c. All wires removed/unsoldered during the
hardware and retain for reassembly.
disassembly procedure, should be tagged for
(4) Remove on nut (10), flat washer (12), and
lockwasher (11) securing the solder lug (13) to the
mounting bracket. Tag solder lug and replace nut,
Make sure that external ac circuit breaker
lockwasher and flat washer on the screw for reassembly.
and battery supply are switched off and
(5) Remove five cable clamps securing the
tagged with a warning not to be turned on
cableform to the interior of the cabinet. Retain the cable
while maintenance is being performed.
clamps and attaching hardware for reassembly.
(6) Refer to figure 4-1 (2). Disengage one
4-6. Removal and Replacement of NDB Board
captive screw (17) securing the 50W pa assembly A1A4
(16). Remove the 50W pa assembly A1A4.
a. Removal. Proceed as follows.
(7) Remove two flathead screws (28), nuts (23),
(1) Refer to figure 4-1 (1). Loosen three screws
lockwashers (24), flat washers (25), and hex pillars (27)
(2) securing the fanning strip (1) to the power probe
securing connector XA4 (22). Identify the attaching
assembly A1A6 (6) terminal strip and disconnect the
hardware and retain for assembly.