Section X. MAINTENANCE OF TTY LOOP MONITOR ASSEMBLY SM-D-936640

TM 11-5895-1123-34

Section X. MAINTENANCE OF TTY LOOP MONITOR

ASSEMBLY SM-D-936640

3-31. Removal of TTY Loop Monitor Assembly

the meter to the monitor assembly front panel. Remove

SMD936640 a. Loosen the four captive screws

the meter.

on the front of the TTY loop monitor assembly.

(4) Install the new meter; secure it to the monitor

b. Pull the TTY loop monitor assembly forward, and

assembly front panel using the hardware of b(3) above.

remove the three cables from the three rear panel

(5) Connect the capacitor across the meter

connectors, J1 through J3.

terminals.

e. Disconnect the grounding cable from E 1 on the

(6) Connect the wires removed in b(l) above to the

rear panel of the loop monitor assembly.

meter terminals and solder.

3-32. Maintenance of TTY Loop Monitor Assembly

c. Replacement of Rear Panel Connectors J1, J2,

SMD936640 a. Replacement of Rotary Switches

and J3.

SI and S2.

(1) Remove the hexjam nut securing the connector

(1) On the defective switch, tag and unsolder the

to the monitor assembly rear panel. Remove the

wires or clip off the wires. If the wires are clipped off,

connector.

leave a piece of wire long enough so that the color code

(2) Transfer the wires, one at a time, from the

is readable.

defective connector to the replacement connector.

(2) Loosen the screw holding the knob and then

(3) Mount the connector on the rear panel and

remove the knob.

secure it to the panel using the hex-jam nut removed in

(3) Remove the hexnut securing the switch shaft to

c(1) above.

the rear of the monitor assembly front panel.

d. Replacement of Terminal Boards A1and A2.

(4) Install the replacement switch on the monitor

(1) Remove the screws, nuts, and spacers from the

assembly and secure it to the front panel.

defective terminal board. Remove the terminal board.

(5) Prepare the wires for soldering. Solder the wires

(2) Install the replacement terminal board using the

to the rotary switch terminals.

screws, nuts, and spacers removed in (1) above.

(6) Replace and secure the knob.

(3) Transfer the wires, one at a time, to the

b. Replacement of the LOOP CURRENT Meter

replacement terminal board.

(M2)and the LOW LEVEL TTY VOLTAGE Meter (M1).

3-33. Replacement of TTY Loop Monitor Assembly

(1) Tag and remove the wires connected to the rear

SMD936640.

of the meter.

(1) Connect the external cables to the rear panel

(2) Unsolder and remove the capacitor terminals

connectors J1, J2, and J3. Also connect the ground lead

(C1 or C2) connected across the meter. Check the

to E 1.

capacitor; if good, save. If the capacitor is defective,

(2) Insert the TTY Loop Monitor Assembly into the

replace it.

rack and tighten the four captive screws securing the

(3) Remove the four screws and nuts securing

panel to the rack.

Section XI. MAINTENANCE OF CONTROL MONITOR

-48V/20Hz ASSEMBLY

3-34. Removal of Control Monitor -48V/20 Hz

pull the assembly forward. When the assembly is clear

Assembly

of the rack, reach in and disconnect the two cable

The control monitor assembly is not secured to

the

connectors.

equipment rack using hardware. It is a force fit.

3-35. Maintenance of Control Monitor 48V/20 Hz

remove the control monitor assembly, grasp two of

the

Assembly ac Replacement of Circuit Breakers

front panel toggle switches and pull forward. If

the

CB1 and CB2.

control monitor assembly will not come out, remove

the

(1) Remove the cover over the defective circuit

1600 Hz ringing supply next to it and then

3-53