Based on the level of testing selected, on-line
maintenance testing can assist in fault isolation by
testing suspected equipment or systems with a mini-
mum of interference with normal ship operation. If a
suspected equipment or system checks out satis-
factorily, then a possible source of the fault has been
eliminated. This aids in the fault-isolation process. In
general, the use of on-line testing provides a quick
fault-isolation tool when you are trying to confirm
equipment or system problems. When using on-line
testing, you should be careful not to degrade the sys-
tem or subsystem operational capability beyond the
level specified by ship doctrine.
Some combat systems equipment has the capa-
bility of severing normal communications links and
accepting preset or manual inputs when you are
verifying system ability to correctly process data. This
off-line testing offers a convenient method of iso-
lating equipment or interface faults. As in on-line
testing, care must be taken not to degrade the system
or subsystem operational capabilities. One such
off-line test is the system maintenance test (SMT)
used in the Mk 86 gunfire control system (GFCS).
The SMP is a computer program that enhances
fictional testing and troubleshooting of the FCS.
The SMP provides test conditions to check the integ-
rity of input/output circuits to and from the computer
and to check the fictional integrity of various
functional systems. It is loaded into the FCS computer
in place of the normal (tactical) FCS operational
program. Therefore, the FCS is not functional in a
tactical sense until the FCS operational computer
program has been reloaded into the FCS computer fol-
lowing the use of the SMP.
The program includes a configuration entry
routine, an executive routine, and approximately 60
individual tests that are organized into groups
according to the interface channels between the
computer and the peripheral units. Configuration
entry allows the technician to adapt the program to a
particular modification of the FCS. The executive
routine provides the basic timing requirements for
each test program and establishes testing priority in
the event two or more tests are selected concurrently.
The tests are grouped according to channel and
unit numbers as follows:
Channel 14 test programs are selected from
units 1, 2, and 3.
Channel 15 test programs are selected from
Channel 16 test programs are selected from
Channel 17 test programs are selected from
A sample of channel 14 test programs is shown in
table 1-1. Notice that the tests selected at unit 2 or 3
are selected with a test number select code. The proce-
dures for setting up these codes are in table 1-2.