Table 4-7. TESTING RECEIVER CIRCUITS TEST PROCEDURE
Preliminaries. The receiving circuits are tested by applying an audio
signal to the received signal pins of the selector unit connectors J201,
J202. The resulting signals between the sleeve terminals of the headset
jack pair (J301, J302) on the jack -panel are then measured. Before
proceeding with the tests, perform the preliminary adjustments of 1a
a. Connect-external power source.
Power light is on.
Depress Power switch.
b. Set S1002 (LOCK/NONLOCK) of first selector module to off (center)
position. See the selector unit, front panel, figure 4-1.
c. Set S1001 (HEADSET-LOUDSPEAKER switch) of first selector
module to HEADSET position.
d. Regulator jumper (E1121 to E1122 in volume control module) must
be in place. See circuit board figure 4-2.
e. Turn HEADSET and SPEAKER volume controls in the audio unit to
maximum position. See audio unit, front panel, figure 4-3.