T.O. 33A1-3-358-11/TM 11-6625-842-15
Section VI
Paragraphs 6-19 to 6-21
NAVAIR 16-30APM239-2
Set the TEST CONDITION switch to VOLTS.
b.
In turn, connect the multi meter test probe to MODE C ENCODER connector J5, terminals s, g,
c.
b, L, f, J, P, T, F, m, and p. The multimeter should indicate between 1 volt and 2 volts at each terminal
to ground.
Set all MODE C ENCODER SIMULATOR switches (C1, A1, C2, A2, C4, A4, B1, B2, D2, B4,
d.
and D4 IDENT) to OFF. Set the multimeter to measure d-c voltage of approximately 20 volts.
e.
In turn, connect the multimeter test probe to MODE C ENCODER connector J5, terminals s, g,
b, L, f, J, P, T, F, m, and p. The multimeter should indicate between 18.5 volts and 21.5 volts at each
terminal to ground.
f.
Disconnect the multimeter.
6-19. PULSE LIMITER CIRCUIT CHECK.
a. Connect test set-to-computer cable W11 between MODE 4 COMPUTER connector J4 on the test
set and MODE 4 connector J1 on Simulator Test Set AN/APM-245.
b.
Connect the oscilloscope preamp input to MODE 4 REPLY connector J4 on Simulator Test Set
AN/APM-245. Set the oscilloscope controls to measure pulses of 10 volts amplitude at a prf of 1000 pps.
CAUTION
Do not attempt to inject pulses into MODE 4 REPLY connector J9. This
is an output connector.
c. Energize Simulator Test Set AN/APM-245 by placing the power switch to ON. Connect a coaxial
jumper cable (BNC connectors) between the INT TRIG connector and M4 TRIG connector of Simulator Test Set
AN/APM-245. Set the Simulator Test Set AN/APM-245 prf range selector to INT-MED and adjust the PRF
control for a prf meter reading of 1000 pps. Operate the MODE 4 REPLY AM control of Test Set Simulator
AN/APM-245 to observe the three-pulse train on the oscilloscope, and adjust the control to obtain a pulse
amplitude of 10 volts. Note the pulse width of the Mode 4 reply pulses.
NOTE
Operation of the other Simulator Test Set AN/APM-245 controls is not
necessary to provide the Mode 4 reply pubes.
Disconnect the oscilloscope preamp input from Simulator Test Set AN/APM-245 and connect it
d.
to the MODE 4 REPLY connector on the test set. The pulses viewed must meet the following criteria:
Amplitude
Between 4 volts-and 6 volts
Pulse width
Same as pulse width of the Mode 4
reply pulses from the simulator test
set 0.05 microsecond
Rise time
0.1 microsecond maximum
Fall time
0.25 microsecond maximum
Negative overshoot
1.5 volts maximum
e. De-energize Simulator Test Set AN/APM-245, remove test set-to-computer cable W11, and set
the 6 AMP POWER circuit breaker to OFF.
6-20. CONTINUITY CHECKS.
6-21. Continuity checks are to be performed only on areas of the test set that have been repaired. When per-
forming continuity checks, use the multimeter as an ohmmeter and refer to the schematic diagram (figure 4-4)
and the wire run list (figure 4-6).
6-5
