Figure 7-31.--Intercommunicating units, types LS-518/SIC and LS519/SIC.

position and depress release push button S 1 on the unit

connecting terminal 2X to terminal XX. When station

under test. This test checks the continuity between

selector push button S2 on the unit under test is

terminals 2 and 2C through switch S2U and busy relay

depressed to select station 2, it checks the busy circuit

K2 to the line winding terminals 14 and 15 of

through lower switch assembly S2L, busy relay K2,

latchbar switch S23, and associated wiring. It also

transformer T2.

checks the operation of upper switch assembly S2U and

Similarly, on the unit under test, depress the

associated wiring.

remaining station selector push buttons, S3 through S11,

Test the remaining push buttons by operating first

using the corresponding test switches, S203 through

S211, on the test fixture for each test. This test checks

the test switches, S204 through S211, to the TEST

the continuity of the various audio circuits. If the unit

position on the test fixture, and then depressing the

under test is provided with facilities for originating calls

corresponding station selector push buttons, S4 through

to 20 stations, repeat the foregoing tests, using the

S11, on the unit under test. If the unit under test is a

second row of station selector pushbuttons, S12 through

20-station type, repeat the foregoing tests, using the

S21.

second row of station selector pushbuttons, S12 through

S21.

Signal Circuit Test

The manufacturer's technical manual furnished

with the equipment installed in your ship contains more

On the test fixture (fig. 7-30), operate talk test

detailed information concerning the operation, repair,

switch S213 to the OFF position and the 11 test switches,

and maintenance of intercommunicating units.

S201 through S211, to the STANDBY position. On the

unit under test, depress release push button S1 for the

INTERCOMMUNICATING UNITS

subsequent signal circuit tests.

LS-518/SIC AND LS-519/SIC

On the test fixture, operate test switch S202 to the

TEST position, and on the unit under test, depress

The N-518/SIC and LS-519/SIC intercoms (fig.

station selector push button S2. Busy lamp I1 should

7-3 1) are 10-station and 20-station units, respectively.

light. On the unit under test, depress release pushbutton

Both are fully transistorized intercoms that operate in

S1, and again depress station selector switch S2. Busy

much the same way as the older 433A and 434A types

lamp I1 should go out and again light. Repeat this test

(refer to the overall functional diagram, fig. 7-32). The

several times in rapid succession. On the test fixture,

darkened solid line in this figure shows that the audio

restore test switch S201 to the STANDBY position, and

from the calling loudspeaker is amplified and

on the unit under test, depress release push button S1.

transmitted via the station selector switches to the called

When test switch S202 on the test fixture is operated

station. The darkened broken line shows that the audio

to the TEST position, it makes station 2 busy by

from the calling station goes into the speaker of the local

Figure 7-31.--Intercommunicating units, types LS-518/SIC and LS519/SIC.

7-32