(3) Remove the two flathead screws
115. Removal and Replacement of Centrifugal
(9) and the two roundhead screws
Fan HD-390/U (AN/TRC-68 Only)
(9) and lockwashers from the top
of the shroud (top view).
The instructions for the removal and re-
(4) Remove one flathead screw (9) and
placement of the dynamotor (para 114) also
one roundhead screw (9) and lock-
apply to Centrifugal Fan HD-390/U, which
washer from each side of the
i s included in Receiver-Transmitter
shroud (left- and right-side views).
Group OA-2649/TRC-68, except that plug
(5) Lift the shroud straight up and off
P1051 is substituted for plug P1001.
(6) Loosen coaxial connector P1301 in
the lower right corner (top view).
116. Removal and RepIacement of 500-Kc
(7) Turn the rt unit over and remove
and Low-Pass Filter Assembly
the four roundhead screws (9) and
lockwashers on the bottom of the
chassis (bottom view).
(8) Tilt the rt unit upward so that it
(1) Set the rt unit on its left side on the
rests on the rear of the mainframe.
Work the front panel carefully to
(2) Disconnect plugs P6, P7, P102, and
loosen plugs P701, P702, and P704
P1101 (right-side view).
(top- and left-side view). These
(3) Loosen one captive screw (11) on
plugs are mounted on the front
the front end of the assembly and
panel and disengage from their
two captive screws (11) on the rear
mating jacks when the panel is re-
end of the assembly (right-side
moved. Pull the front panel straight
(4) Lift the filter assembly out of the
up from the chassis.
chassis. The 500-kc and low-pass
filters can be separated for indi-
(1) Center the front panel on the chas-
vidual replacement by removal of
the four screws that fasten the fil-
sis; make certain that jacks J7,
J1201, and J9, and ANT. jack J701
mate properly with plugs P701,
P702, P704, and P1301 (top- and
(1) Replace and tighten the four screws
that fasten the filters together (if
(2) Tighten plug P1301 (top view).
(3) Replace the four roundhead screws
(2) Seat the filter assembly on the
(9) and lockwashers on the bottom
chassis and align the captive
of the chassis (bottom view). Do not
screws with the holes.
(3) Tighten the three captive screws
(4) Connect plug P703 (left-side view).
(11) (right-side view).
(5) Slide the shroud into place from the
(4) Connect plugs P6, P7, P102, and
top of the chassis.
P1101 (right-side view).
(6) Replace the flathead screw and the
roundhead screw (9) and lock-
washers on each side of the shroud
117. Removal and Replacement of Front
(left- and right-side view). Do not
(7) Replace the two flathead screws
and the two roundhead screws (9)
(1) Set the rt unit top side up on the
and lockwashers in the top of the
shroud (top view).
(2) Disconnect plug P703 (left-side
(8) Tighten all screws around the