TM 11-5821-333-30
6-6. TEST ADAPTER
The test adapter provides the following services:
l Provides physical support for the reference radio equipment,
Supplies ac and dc power to the reference radio and units under test that are connected,
Provides connections for inputs and outputs of the test equipment and switches for routing desired sig-
nals to and from the test equipment,
Switches and routes rf signals between rts and to test equipment for diagnosis,
Switches and routes control signals from reference radio to unit under test,
Shows status of signals between reference and under test radios with status lights,
l Provides access to signals between reference and under test radios with test points,
Provides audio input and output to the radios through the headset,
Sets test conditions to simulate different modes of operation.
See figure FO-16 for a schematic of the test adapter.
The test adapter can be divided into the following sections:
l Power supply,
l Test equipment connection and routing,
Rf section,
l Routing switches,
l Test lamps,
l Test condition switches,
l Test points.
Each of these is covered in the following paragraphs.
a. Power Supply. Dc power at a +28 V level is input at connector J21. It may be switched on and off with the
DC switch, which is circuit breaker CB2. When dc power is on, the DC lamp (DS12) is lit. The +28 V may be tested
at TP23. A +6.75 V level is supplied to TP22. This may be used to power the digital logic probe during trouble-
shooting. The +28 V is supplied to all reference and unit under test radio units.
Ac power is input at a 115 V ac !evel at connector J20. It may be switched on and off with the AC switch, which is
circuit breaker CB1. When ac power is switched on, the AC lamp (DS11) will be lit. Ac power is supplied to rt and
rcu units under test.
b. Test Equipmenf Connection and Routing. Connectors J8 through J19 provide input and output ports for
test equipment connection to the test adapter. Figure 6-3 gives a partial schematic diagram of the test equip-
ment inputs, outputs, and switching. The routing switches of the test adapter send signals for testing to the test
equipment input (TEST EQPT INPUT) switch, S14. When S14 is set for internal signals (INTL), the selected signal
is routed to the test equipment, If S14 is set to EXT, then the signal tested will be the one sampled by the external
probe (EXT PROBE) connected to J8. S14 sends the selected signal to the TEST EQUIPMENT SELECTOR, S15.
Depending on the setting, S15 may send the signal to:
l the headset via the its,
l scope channel 1 (SCOPE),
l the digital multimeter (DMM),
l the frequency counter (FREQ CNTR).
The calibrate switch (CAL, S7) will, when set to IN, route the input function generator signal (FCTN GEN) to both
the frequency counter and scope channel 2. This allows the operator to set an input signal’s frequency and level
without moving cables.
6-5
