TM 11-6625-422-40
MAINTENANCE OF AN/URM-157
Section Ill.
b. When repairing cables, refer to the sche-
3-6. General Parts Replacement Techniques
matic diagram of the cables (fig. 313) to insure
Most of the parts of the test unit can be reached
proper connection between jacks. Use the sche-
and replaced easily without special procedures
matic diagram (fig. 310) and the wiring dia-
after removal of the bottom cover. In some cases,
gram (fig. 315 ) to trace the circuits when re
it is necessary to remove the dummy antenna
pairing the control unit.
assembly to make parts accessible.
a. Before a part is removed, note the position
3-7. Replacement Data
of the part and its leads, and label all leads
After replacing RF OUTPUT meter Ml, check
where necessary. Install the replacement parts in
the calibration (para 314).
the same position as the original parts.
GENERAL SUPPORT TESTING PROCEDURES
Section IV.
3-9. Test Equipment and Materials Required
3-8. General
.
a. All test equipment and materials required to
a. Testing procedures are prepared for use by
perform the testing procedures given in para-
Signal Field Maintenance Shops and Signal Serv-
graphs 3-11, 312, and 313 are listed in the fol-
ice Organizations responsible for general support
lowing charts.
maintenance of electronic equipment to deter-
mine the acceptability of repaired equipment.
b. The only test equipment required for the
These procedures set forth specific requirements
general support testing procedure is Multimeter
that repaired electronic equipment must m e e t
Meter ME-26B/U.
before it is returned to the using organization.
3-10. Modification Work Orders
Equipment that meets the minimum standards
stated in the tests will furnish satisfactory opera-
The performance standards listed in the tests
tion equivalent to that of new equipment. The
testing procedures may also be used as a guide
assumption that applicable modification work or-
t o test equipment repaired by direct support
ders have been performed. A listing of current
maintenance personnel if the proper tools and
modification work orders will be found in DA
test equipment are available. A summary of the
Pam 3107.
performance standards is given in paragraph 3
15.
3-11. Physical Tests and Inspections
a. Test Equipment and Materials. None.
b. Comply with the instructions preceding the
body of each chart before proceeding to the chart.
b. Test Connection and Conditions.
Perform each test in sequence. Do not vary the
(1) No connections necessary.
sequence. For each step, perform all the actions
(2) Remove the control unit from the test
required in the Control settings columns; then
unit.
perform each specific test procedure and verify
(3) Remove the bottom cover from the test
unit.
it against its performance standard.
c. Procedure.
Control settings
Step
Performance standard
Test procedure
Test equipment
Equipment under test
No.
a. No damage evident or
a. Inspect case and chassis
Not applicable . . . _
Controls and switches may be
1
parts missing. External
for damage or missing
in any position.
surfac- intended to be
parts, and for condition
painted will not show
of paint.
NOTE-
-bare metal. Panel let-
Touchup painting is recom-
tering will be legible.
mended instead of refinishing
whenever practical; screw-
heads, binding posts, recep
tacles, and other plated parts
3-8
