7-2. TROUBLESHOOTING METHODOLOGY
Troubleshooting is the process by which a problem is detected (identify that a
problem exists), isolated (eliminate from a suspect group the cause of the problem),
and repaired (restore system to proper operation).
Troubleshooting methodology is
the method or how a problem is detected, isolated, and repaired.
TADS/PNVS augmentation equipment uses a combination of built-in-test equipment
(BITE) and operator interface/interaction to detect, isolate, and repair system in
the shortest time possible.
TADS/PNVS augmentation equipment fall into the
Cabinets, Slides, Base
Blowers, Lamps, Etc.
These categories are discussed in later paragraphs.
Faults can be detected by visual inspection, symptoms, functional
inference, and automatic diagnostic testing using BITE and software programs.
Troubleshooting of TADS/PNVS augmentation equipment is done in this manner.
Testing and troubleshooting of various electronic, electrical, electro-
mechanical, and optical assemblies are done using BITE and a self-test program.
This program contains 37 stand-alone self-test modules. Each module tests a
particular function or system operation (refer to chapter 2 for an explanation of
self-test program and procedures).
If no faults are detected, a pass message is
displayed on the VDT.
If a fault is detected, a failure message is displayed on
Each self-test module will isolate a fault to a single function operation.
This operation is dependent on a group of parts performing properly. To isolate the
parts, each part is replaced beginning with the part most likely to fail. This
continues until the part least likely to have failed is replaced. This will
eliminate each member of that group until the failed part is found. Replacement
order is displayed on VDT screen.
When a malfunctioning part is identified, it is repaired and restored to
its proper operation.
Often, isolation and repair happen at the same time. During
isolation, a part is replaced and self-test performed to verify system performance.
If system does not function properly, then the next item is replaced. If system
does function properly, then last item replaced is bad. This item is either
repaired, sent to depot for repair, or discarded as applicable.