TM 11-6625-2398-15-3
panel of the receiver-transmitter.
CAUTION
b. To monitor signals at the individually labeled test
To avoid damage to the equipment under test
jacks, connect the appropriate external test equipment
DO NOT energize Interrogator Set AN/TPX-50
(e.g., multimeter, differential voltmeter etc.) to the test
before terminating jacks J9 and J10. If testing
jack of interest and to GND test jack J8 on the front
without the hybrid attenuator, terminate cable
panel test adapter, and observe the reading on the
W45 and adapter CP7/CP8 with terminations
external test equipment.
AT3/AT4.
c. To monitor signals at the VIDEO jack, connect an
(3) The insertion losses marked on the tags attached
oscilloscope to the VIDEO jack using a high impedance
to the hybrid attenuator and connecting coaxial cables
probe (Test Probe MX-2817/U or equivalent, refer to TM
(e.g., W14/W15 and/or W39) have to be taken into
11-6625-535-15), ground the probe to GND jack J8,
consideration when figuring the attenuation in dB for
select the signal of interest on the VIDEO switch, and
setting the ATTENUATOR control.
observe the signal on the oscilloscope.
3-11.
Typical Connection and Use of Minor
3-10. Operation of Hybrid Attenuator
Components
The hybrid attenuator is provided to facilitate testing,
Certain of the minor components of the test facilities set
troubleshooting and alignment/adjustment of the
are standard general-purpose adapters and terminations
receiver-transmitter in the iff set. All of the specific uses
which are used in a large number of the test set-ups
of the hybrid attenuator with the receiver-transmitter are
required in maintaining the complete iff set. Included in
described in TM 11-5895-687-35-4. Operation of the
this category are adapter CP7/CP8 (N-male to BNC
hybrid attenuator as an attenuator (a below) and in
female adapter, type UG-201A/U), adapter CP9/
typical receiver and transmitter test configurations (b
CP10/CP11 (BNC tee, type UG-274B/U), termination
below) are as follows:
AT3/AT4 (50-ohm dummy load, type DA-558), and
termination AT5/AT6 (75-ohm dummy load, type DA-
a. Challenge Monitor Test. The attenuator portion of
559). General instructions for connecting the remaining
the hybrid attenuator is used to attenuate the power
minor components of the test facilities set are provided
output of the transmitter in the iff set before it reaches
below.
the if strip line coupler (1A3A5) to determine if the
challenge monitor indicator is operating within the
a.
Extender Boards and Printed Circuit Board
prescribed limits. Refer to TM 11-5895-687-35-4 for the
Extractors
detailed procedure of this test.
(1) Printed circuit (pc) board extractor MP2 is
b.
Typical Hybrid Attenuator
Receiver
and
used to remove any pc board in the processor or
Transmitter Test Configurations.
synchronizer assembly of the iff set or pc boards
1A3A1A1 and 1A3A2A1 of the receiver-transmitter
(1) The test connections between the iff set and
assembly. Remove power from the iff set. Remove the
the hybrid attenuator, shown in figure 3-4, are typical for
chassis and release the retaining cover on the module.
most of the receiver and transmitter tests on the iff set.
Insert the tines of MP2 into the holes at the top of the pc
Consult the individual test procedure in the TM 11-
board and pull out the board.
5895-687-35-4 for possible deviations in the test
connections and for prescribed settings of the
(2) Printed circuit board extractor MP1 is used to
ATTENUATOR control.
remove pc boards 1A3A3A2A3, 1A3A3A2A4 or
1A3A3A2A4 of the receiver-transmitter assembly in the
(2) Cable W45 and adapter CP7/CP8 enable
iff set. Remove these pc boards as described in (1)
connection of cables W14/W15 from the hybrid
above.
attenuator to the RF sum (J9) and RF difference (J10)
channels, respectively.
(3) Extender boards A3/A4 provide maintenance
accessibility for the pc boards removed by pc board
extractor MP2, (1) above. Remove the pc board and
insert the extender board in
3-6
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