Indexing of Related Information

A solid black rectangle and white lettering represent

charts. Faults must lie between the first bad event and

the last good event. Acetate coverings for MDCs may

a front panel indicator or an event recognizable from

be provided, or the charts maybe plasticized, so a grease

outside the cabinetry; an outlined rectangle with black

or carbon pencil can be used for marking out areas that

lettering is a circuit point at which measurement might

prove good. Marking out all known areas and actions

at some time be made. This circuit point may not be

readily accessible. Internal test points that are readily

that can be proven good rapidly reveals suspect areas.

The use of a pencil to mark out all proven good items is

accessible will be shown as gray-shaded rectangles.

recommended because technicians cannot normally

The dot () represents a circuit element or a

remember all the areas or dependencies that they have

functional entity. One aspect or state of circuit or

proven good.

component is represented by (), and relay contacts are

shown by (/) or (/), for continuity with relay energized

INDEXING OF RELATED INFORMATION

or de-energized, respectively.

Indexing is another important feature of the SIMM.

HOW TO USE THE MAINTENANCE

The SIMM method of indexing (fig. 4-7) allows access

DEPENDENCY CHART

to any bit of information relative to an assembly in a

matter of seconds. The index is organized on the basis

Assume that in the illustration of a signal event line,

of major assemblies and then is broken down to the

figure 4-6, view A, dots () represent the basic circuits

contained assemblies. Since each of the assemblies is

(oscillator stages, amplifier stages, and soon) or circuit

full y treated within a four- or six-page data package, and

elements (relay contacts, relay cards, and so on) that

the organization of details is always consistent, access

provide an action LIT at the end of a circuit chain (event

to the desired kind of detail is almost immediate. The

line). The solid triangle

is a dependency marker.

MDC is used to identify the functional entity or circuit

The action LIT depends on the availability of a

element that is suspected, the assembly in which it is

power source at the A block and on the proper operation

contained, and the cabinet containing the assembly.

Accordingly, in using the index you need only find the

of each of the circuits or circuit elements () represented

cabinet nomenclature and look to the page number for

along the event line. Now, if the lamp that indicates the

the contained assembly data package.

action fails to light, any item along the event line, as well

as the source, A, is a suspect item. Complex interrelated

circuits often use some of the same circuits or circuit

ALIGNMENT PROCEDURES

elements for more than one purpose. Thus, in multiple

circuits, where many functional items are common to

Alignment procedures for each functional section

more than one circuit chain (event line), as shown in

of the set or system, as necessary, are included on as few

figure 4-6, view B, notice that actions (column 24) that

pages as possible. The method of identifying alignment

occur at the end of these circuit chains are a result of

procedures is the same as for making other

certain common items employed in the parallel

identifications from the MDC. The alignment

generation of the events shown on other circuit lines and

procedures are directly keyed from the signal

some items that are unique to a single line.

specifications listed on the MDC. If a particular event

Look again at the multiple event line illustration

shown on the MDC is below specification and

(fig. 4-6, view B) for the purpose of analysis. If the lamp

correctable by alignment, the step in the alignment chart

does not light on line 4 but does light on lines 1, 2, 3,

is easy to find. Each part of the MDC treats a major

and 5, it becomes apparent that the circuits or circuit

functional segment of equipment. Likewise, the

elements represented by the dots in columns 4 and 18

alignment actions are organized (charted) for each major

are the only ones that can be suspected as faulty. All

fictional segment of the equipment. The identification

items represented by dots in other columns are proven

system for the charts is used for the alignment procedure

good because of the proper occurrence of the action LIT

chart. For example, alignments that affect events on the

on lines 1, 2, 3, and 5.

MDC, part 2, will be found on the alignment chart, part

For each major circuit, consistent with the

2 , and so on. When required, alignment of

precise-access blocked diagrams and blocked

subassemblies outside the set environment will be

s c h e m a t i c s , there is a corresponding MDC.

contained with the other details of individual assemblies

Troubleshooting is accomplished by analyzing the

in the data package for the assembly.

4-7