Figure 4-5.-Precise-access blocked text.

Figure 4-5.-Precise-access blocked text.

In each basic shape is inscribed the circuit-identifier

line. Monitors are indicated in a solid black background

code that identifies the actual component. In addition,

box with white lettering.

the coded arrows superimposed on the signal-flow lines

Front panel indicators and other recognizable

that tie these shapes together are again used to identify

indications with front panel markings, as applicable, and

the signals being processed. Also superimposed over

their associated cabinet nomenclature are located along

these block diagrams are shades of gray that indicate the

the top of the chart, If an event fails to happen, fault

level of containment of the components or other circuit

isolation is simplified by the indexing on the operator's

elements in the equipment through which the signal or

chart. This indexing will lead the troubleshooter to the

signals pass. Again there is blocked text on the facing

proper maintenance dependency chart and the circuit

page (fig. 4-5).

chain upon which the missing event depends. The

Detailed cabling information between all

troubleshooter merely associates the operational step

assemblies is shown on the precise-access blocked

and the event that did not occur to find the pertinent

diagram. In cases of large complex equipment, however,

circuit chain. A vertical column on the left side of the

power circuit cabling is detailed on power distribution

page contains the turn-on procedure in a sequence of

diagrams.

steps consistent with the engineering designed plan of

turn-on. Also in the left-hand column, boxed and

indented, are checkout procedural steps that can be

OPERATING PROCEDURES

performed at any time during operation. These checkout

steps will give an indication of the functional

Procedures that explain how to operate equipment

performance and will provide a sound basis for selection

under normal and emergency conditions are included in

of operator, preventive-maintenance checks.

the operating procedures. Manuals for some equipment

contain an operating chart that establishes a turn-on and

MAINTENANCE DEPENDENCY CHART

checkout procedure. The chart displays chronologically

all indications that can be recognized from outside the

equipment. The indications are events, such as meter

One of the most important features of the SIMM is

readings, lights, synchro rotating, or motor running

its troubleshooting tool, the maintenance dependency

noise, that can be recognized by the human senses.

chart (MDC). In addition to front panel marked

Shaded bands stretching across the chart show the time

indicators displayed across the top of the page, it

lapse between events. All simultaneous events for a

contains the various assemblies or circuit elements

given step of the procedure appear on one horizontal

through which a signal passes, as well as their chassis

4-5