(3) Replacement. Replace the feedcone subassembly
if the unit fails any check made in (1) or (2)
above.
b. Balun Assembly (fig. 6-1).
(1) Visual inspection.
(a) Inspect the Lexan/balun housing for cracks
or evidence of deterioration. Replace the balun housing
if unit fails inspection.
(b) Inspect the UG-680/U for damage to the
connector threads or center pin. Replace the
UG-680/U following the disassembly procedure of
paragraph 6-5 a if connector fails inspection.
(c) Inspect the balun subassembly for broken
wire leads or poor solder joints. Repair or replace wire
leads and solder joints if unit fails inspection.
(2) Continuity Check. Disassemble unit if required,
using the disassembly procedure of paragraph
6-5 a. Check the continuity between the shell and
center conductor of the UG–680/U connector and
between the #4 terminal wire lead (white) and #6 terminal
wire lead (black) (fig. 6-1) using a low
resistance range on the ohmmeter. Resistance
readings should be near zero indicating direct continuity.
Repair or replace the UG-680/U connector
or balun subassembly if unit fails the test.
c. CG—1889C/U.
(1) Check the continuity of the coaxial cable
center conductor using a low resistance range of the
ohmmeter. The resistance should be near zero. An
open circuit is indicated by a resistance reading of infinity.
(2) Check the coaxial cable for a short circuit
between the wire braid and the center conductor, using
the highest resistance range of the ohmmeter. The
resistance should be nearly infinite if no short is present.
(3) If required readings are not obtained in (1) or
(2) above, repair the CG-1889C/U by replacing the
cable or by shortening the cable by severing a defective
end and replacing the connectors per cabling
procedure of figure 6-7. The cable should be a
minimum 50 feet in length.
(4) Check the continuity between the connector
center pin and outer conductor using a low resistance
range on the ohmmeter, The resistance should be
zero. Repair or replace connector per cabling
6-