TM 9-4935-294-15/2
(10) Disassemble waveguide assembly and BWO
lead to terminal 2 on dispersion PC board assembly
tube by removing four hex nuts (6), four washers (7),
(refer to 1, fig. 412).
and screws (8).
(11) Install connector bracket assembly (3, fig. 4-
b. Replacement of BWO Tube 79$l111.
25) on rf head chassis (89) with two screws (4) and
secure.
(1) Obtain a replacement BWO tube; unpack and
(12) Connect and solder the green, orange, and
inspect for possible shipping and/or handling damage. If
blue harness leads to connector bracket assembly (3)
BWO tube is in satisfactory condition, proceed with the
installation. Perform installation procedures in a location
(13) Install side cover (1, fig. 425) and attach with
free from possible magnetic fields. Use a work surface
10 screws (2).
that is non-magnetic.
c. Disassembly of U-Band Rf Head. To disassemble
(2) Remove protective cover from the output
the U-band rf head completely, follow the order of
connector.
(3) Obtain three replacement male connector
contacts 7928076. Obtain installation and crimping
assembly of the connector bracket assembly and counter
tool 7919871.
assembly, refer to e and f, respectively, below.
Note. To install male connector contacts, follow the
d. Assembly of U-Band Rf Head. To assemble the U-
band rf head, refer to exploded view, figure 425, and
(a).
wiring diagram, figure 426, and reverse the order of
(4) Install male connector contact 19 (refer to 18,
disassembly.
fig. 412) on brown harness (helix) lead.
Note.
Apply sealing compound A10628558 or
(5) Install male connector contacts 7 and 16 on
A106286657, as applicable and required, to all screws
yellow harness (heater) leads.
not secured with locking devices (refer to paragraph
428).
the tube output connector. Attach with four screws (8)
e. Disassembly and Assembly of Connector
inserted through the waveguide flange and output
Bracket Assembly. To disassemble and assemble the
connector engagement. Secure with four washers (7)
connector bracket assembly, refer to exploded view,
and four nuts (6).
(7) Place assembled tube and waveguide
assembly in proper position within the rf head chassis
e.
(89) and aline tube brackets with mounting holes. Insert
f.
Disassembly and Assembly of the Counter
screws (10) through rf head chassis (89) into the
Assembly.
mounting brackets. Do not tighten at this time as tube
(1) Disassembly. To disassemble the counter
must be free to move.
assembly,
follow the order of removal shown in
Note. Tube harness is routed between the bottom of
the chassis and the tube.
(8) Carefully aline waveguide flange with flange of
(2) Assembly. To assemble the counter assembly,
directional coupler (18) and waveguide support (87).
Insert two screws (9) through this engagement and
secure on the coupler side with two washers (7) and nuts
Observe the following procedures:
(6). Insert two screws (8) through the other side of the
waveguide and flanges of directional coupler (18) and
counter assembly (19) with type III, MIL-E-5092A
secure with two washers (7) and two nuts (6).
adhesive.
(9) Apply sealing compound A10528558 to BWO
(b) Obtain gears (16) and (17). If they are
tube (5) bracket mounting screws (10), then tighten.
replacements, ascertain that they are the proper parts
Check position, routing and condition of harness.
and have been inspected.
(10) Connect and solder the red harness
(c) Turn variable resistor R1502 (18) fully ccw.
(d) Set dials of counter assembly (19) to low
Change 1 4-43