Figure 5-17.--Switchlng circuit of AM-2210/WTC.

Figure 5-17.--Switchlng circuit of AM-2210/WTC.

out and communications between any of the local and

stations. The amplifier is effectively bypassed. The

remote stations takes place at the normal sound-

advantage of this circuitry is that any casualty, such as

powered level.

loss of power, will allow normal sound-powered

communications to continue.

Amplifier Maintenance

POWER SUPPLY.-- The power supply is

basically a full-wave rectifier receiving its power

Although by no means trouble free, the

through switch S1 (fig. 5-16) and the fuses on the face

AM-2210/WTC is a highly reliable piece of equipment.

of the amplifier. A neon glow lamp and a volume control

When trouble does occur, it is often caused by improper

potentiometer are also located on the face of the

operating procedures or by a failure in external circuitry.

amplifier. The amplifier operates on 115-volt, 60-Hz,

Often personnel who operate the amplifier are not aware

single-phase power, which is normally supplied by the

of its operational capabilities, and a brief indoctrination

ship's local lighting panels.

will clear up an apparent trouble.

AMPLIFIER OPERATION.-- Incoming signals

One procedure that has caused some failures in the

are amplified and delivered to local headset-chestsets

amplifier is the practice of taping closed the talk button

and loudspeakers. The volume control knob located on

of one of the local headset-chestsets. This violation of

the face of the amplifier is used to adjust the desired

circuit integrity will result in K1 being continually

headset-chestset receiver output volume. The output

restored, resulting in no amplification of incoming

volume for the associated loudspeakers is adjusted

signals.

locally at the loudspeakers. The circuit associated with

You should accomplish preventive maintenance

the telephone amplifier operates under the three

using the applicable maintenance requirement cards

following conditions:

( M R C s ) . You should accomplish corrective

maintenance according to the applicable technical

1. When the amplifier is de-energized, direct

manual.

two-way communication between local and remote

stations takes place at the normal sound-powered level.

AMPLIFIER CONTROL SWITCHES

2. When the amplifier is energized, incoming

signals from the remote line are amplified and

At stations where it is desired to maintain two-way

transmitted to the local stations and associated

communication for all circuits serving the station, an

loudspeakers.

amplifier control switch is installed. This switch

provides the operator with a means of selecting anyone

3. When the amplifier is energized and the talk

of several circuits to be amplified while retaining

switch of any local station is closed, the amplifier is cut

5-19