Test Equipment

Removal of the case or rear cover of an instru-

After soldering, disconnect the iron from its

ment not equipped with an interlock will allow

power supply and let it cool before you store it.

access to circuits carrying voltages dangerous

to human life.

TEST EQUIPMENT

Do not change tubes or make adjustments in-

Test equipment is precision equipment that must

side equipment with the high-voltage supply

be handled with care if it is to perform its designed

energized.

functions accurately.

Under certain conditions, dangerous potentials

Some hazards to avoid when using test equipment

may exist in circuits. With the power controls

include rough handling, moisture, and dust. Bumping

in the OFF position, capacitors can still retain

or dropping a test instrument may distort the

their charge. Therefore, to avoid electrical

calibration of the meter or short-circuit the elements

shock, always de-energize the circuit, discharge

of an electron tube within the instrument.

the capacitors, and ground the circuit before

Moisture effects are minimized in some types of

working on it.

electronic test equipment, such as signal generators

Only authorized maintenance personnel with

and oscilloscopes, by built-in heaters. These heaters

proper approval should be permitted to gain

should be operated for several minutes before high

access to enclosures, connect test equipment, or

voltage is applied to the equipment.

test energized circuits or equipment.

Meters are the most delicate parts of test

Circuits should be de-energized and checked

equipment. You should protect a meter by ensuring

for continuity or resistance, rather than

that the amplitude of the input signal being tested is

within the range of the meter.

energized and checked for voltage at various

points.

Since the moving coils of the meter in electronic

test equipment are of the limited-current type, they can

When a circuit or a piece of equipment is

be permanently damaged by excessive current. To

energized, NEVER service, adjust, or work on

avoid such an occurence, you should observe the

it without the assistance of another person.

following safety precautions and procedures when

using test equipment:

HAND TOOLS

Never place a meter near a strong magnetic

field.

As an IC Electrician, you will be working with

Whenever possible, make the connections

various hand tools on a daily basis. For your safety,

when the circuit is de-energized.

you should take certain precautions when working

with hand tools.

When connecting an ammeter or the current

coil of a wattmeter or other current-measuring

Keep your tools in good condition, and never use

device, always connect the coils in series with

damaged tools. Tools having plastic or wooden

the load--NEVER ACROSS THE LINE.

handles that are cracked, chipped, splintered, or

broken may result in injuries to personnel from cuts,

When voltmeters are used, they should always

bruises, particles striking the eye, and the like.

be connected in parallel with the line.

Use each tool only for the job for which it was

Extend wires attached to an instrument over the

designed. Be careful to avoid placing tools where they

back of the workbench or worktable on which

could fall into mechanical or electrical equipment.

the instrument is placed and away from

observers--never over the front of the work-

Metallic tools used for working on electrical or

bench.

electronic equipment must be covered with an

electrical insulating material. The tools must be coated

Place a mat or folded cloth under the test instru-

with platisol or covered with tape, If tape is used, two

ment when it is used in high-vibration areas.

layers of rubber or vinyl plastic tape, half-lapped, is

required. Cover the handle and as much of the shaft of

Remember that interlocks are not always

the tool as practical.

provided and that they do not always work.

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