Section III. MAINTENANCE OF IF PATCH PANEL

TM 11-5895-1123-34

b. Push the patch panel into the rack.

rack and push it to allow for the connection of the two

c. Secure the patch panel to the rack by inserting

lines to the rear of the unit.

b. Connect the two line cords to the rear of the test

and tightening the four mounting screws.

d. Replace the transmission test set as outlined in

oscillator and voltmeter.

c. Push the transmission test set completely into

paragraph 3-8 below.

the rack and tighten the four captive screws on its front

3-8.

Replacement of the Transmission Test Set

panel to secure it to the rack.

SM-F-935746

a. Position the transmission test set in front of the

Section III. MAINTENANCE OF IF PATCH PANEL

SM-F-935727

g. Remove the ground lug from the wing nut

NOTE

ground stud on the rear frame of the panel.

The C/N test set must be removed from

h. Remove the multipin connector.

the rack in order to remove and replace

i. Tag, if necessary, and remove the 24 cables

the IF patch panel.

from the rear frame by releasing the bayonet connectors.

3-9.

Removal of the C/N Test Set TS-3580

j. Completely remove the IF patch panel.

WARNING

3-11. Maintenance of IF Patch Panel SM-F-935727

Two persons are required to perform the

a. Replacement of Xmit IF Patch/Receive IF

procedure below due to the weight of the

Patch/IF Monitor Subpanels.

unit.

a. Turn ac power off to rack five.

NOTE

b. At the front panel, remove the four screws which

Individual jacks and connectors on the

hold the test set to the rack frame.

front panel cannot be replaced.

c. Pull the test set forward until it is fully extended

Therefore, the entire subpanel on which

the defective unit is located must be

from the rack.

d. Release the slide latches and remove the test

replaced.

(1) Remove the IF patch panel from its rack as

set from the slides.

outlined in paragraph 3-10 above.

e. Push the slides back into the rack.

(2) Tag the cables and remove them from the

f. Rest the test set on the top of the modem rack

rear of the jacks on the subpanel by releasing the BNC

extension.

connectors.

g. Tag the two coaxial cables at the rear of the test

(3) Remove the six screws holding the

set and remove them by unscrewing the TNC

subpanel to the front of the patch panel by turning them

connectors.

counterclockwise while holding the nuts on the inward

h. Snip the nylon tie wrap which holds the ac power

side to prevent their rotation.

cable to the cable retractor arm.

(4) Remove the subpanel from the frame.

i. Unplug the ac power cable from the outlet in the

(5) Insert the replacement subpanel back into

rear of the rack and completely remove the test set.

the frame and secure it to the front panel with the six

3-10. Removal of IF Patch Panel SM-F-935727

mounting screws.

a. Remove the C/N test set using the procedure in

(6) Reconnect the cables to the rear of the

paragraph 3-9 above.

jacks.

b. Loosen the four captive screws on the front

(7) Place the patch panel back into the rack by

panel that hold the IF patch panel to the rack.

following the procedures in paragraph 3-12 below.

c. Pull on the two handles to extend the IF patch

b. Replacement of a Directional Coupler (DC)

panel from the rack.

(1) Remove the IF patch panel from the rack

d. Release the slide latches and remove the IF

by using the procedures in paragraph 3-10 above.

patch panel from the slides.

(2) Tag and remove the two coaxial connectors

e. Push the slides back into the rack.

from the defective directional coupler.

f. Rest the IF patch panel on the modem rack

(3) Tag and remove from the rear panel the

extension.

two BNC through-panel connectors that are above the

3-34