Figure 2-32.AN/USM-465 Portable Service Processor.
The AN/USM-465 is part of the Support and Test Equipment Engineering Program (STEEP). It
provides on-site screen testing and fault isolation of digital pcbs and modules. The psp is presently
available on most ships and shore intermediate maintenance activities (SIMA) with Mini/Micro
maintenance stations (2M). Psps come with maintenance-assist modules (spare parts kit) and diagnostic
The psp is easy to use. You have a choice of three pcb connectors (located on the top panel of the
test set) into which you insert the pcb being tested. The software program, which is provided on magnetic
tape cartridges, is then loaded into the test set. The test set automatically tests the pcb by applying input
signals to the appropriate pins while monitoring the output signal for a correct indication. An LED display
will give you a pass or fail indication. If a pcb fails the operational test, the psp tells you (via LED
display) what troubleshooting steps must be taken. The psp uses a guided probe fault isolation technique
that tells you what test points to check on the faulty pcb. The software program guides you from the faulty
output backwards toward the input until the fault is located. The probe is a standard 10 megohm, 10 to 1
oscilloscope probe. The guided probe circuitry and software is also unique because it is capable of
locating faults within feedback loops and can sense when you have placed the probe at an incorrect test
An interesting advantage is that if the psp itself fails, the faulty board inside the psp can be identified
by the test sets own capability. After you replace the faulty pcb with a good one from the spare parts kit,
you can use the psp to identify the faulty component on its own pcb.
HUNTRON TRACKER 2000
The Huntron Tracker 2000, shown in figure 2-33, is a versatile troubleshooting tool used to statically
test resistors, capacitors, inductors, diodes, transistors, multiple-component circuits, and integrated
circuits. Its built-in features eliminate the use of multiple pieces of test equipment. These features and its
lightweight portability make the 2000 a widely used tool for troubleshooting.