spection requirements to identify an item or range of
TM 11-5820-518-20, Radio Set AN/ARC-51X and
c. The illustrations in this manual are identical to
those published in TM 11-1520-236-34P. Only those
When a stock numbered item is requisitioned,
parts assigned the third position SMR maintenance code
the repair part received may have a different
"C" or "O" are listed in the tabular listing; therefore,
part number than the part being replaced.
there may be a break in the item number sequence. Only
e. Federal Supply Code for Manufacturer (FSCM).
illustrations containing organizational authorized items
The FSCM is a 5-digit numeric code listed in SB
708-41/42 which is used to identify the manufacturer,
appear in this manual.
distributor, or Government agency, etc.
5. How to Locate Repair Parts
f. Description. Indicates the Federal item name and,
a. When National stock number of part number is
if required, a minimum description to identify the item.
g. Unit of Measure (U/M). Indicates the standard of
the basic quantity of the listed item as used in perform-
(1) First. Using the table of contents, determine the
functional group within which the item belongs. This is
ing the actual maintenance function. This measure is ex-
necessary since illustrations are prepared for functional
pressed by a two-character alphabetical abbreviation
groups and listings are divided into the same groups.
(e.g., ea, in, pr, etc). When the unit of measure differs
from the unit of issue, the lowest unit of issue that will
(2) Second. Find the illustration covering the func-
tional group to which the item belongs.
satisfy the required units of measure will be requisitioned.
h. Quantity Incorporated in Unit. Indicates the quan-
(3) Third. Identify the item on the illustration and
tity of the item used in the breakout shown on the il-
not the illustration figure and item number of the item.
lustration figure, which is prepared for a functional
(4) Fourth. Using the Repair Parts Listing, find the
group, subfunctional group, or an assembly.
figure and item number noted on the illustration.
b. When National stock number or part number is
4. Special Information
(1) First. Using the Index of National Stock
a. Usable on codes are shown in the description col-
Numbers and Part Numbers, find the pertinent Na-
umn. Uncoded items are applicable to all models. Iden-
tification of the usable on codes used in this publication
tional stock number or part number. This index in in
NIIN sequence followed by a list of part numbers in
alphanumeric sequence, cross-referenced to the illustration
figure number and item number.
(2) Second. After finding the figure and item
number, locate the figure and item number in the repair
b. The following publication pertains to the
AN/ARC-51X and AN/ARC-51BX and their com-
(Next printed page is 4)