Test Equipment and Tools Required - TM-11-6625-667-450038

TM 11-6625-667-45/NAVAIR 16-30APM123-2/TO 33A1-3-367-22

Test point

measurements in this equipment only as directed on

Test point color

number

the voltage and resistance diagrams. For transistor-

Yellow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ized circuits, use only the ohmmeter ranges

Green . . . . . . . . . . . . . . . . . . . . . . . .

s p e c i f i e d on figures 3-8 through 3-18; otherwise,

Blue . . . . . . . . . . . . . . . . . . . . . . . . . . .

indications will be inaccurate.

Violet . . . . . . . . . . . . . . . . . . . . . . . . .

CAUTION

Gray . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Before using any ohmmeter to test transis-

White . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

tors or transistor circuits, check the open

(5) Extender board. Measurements to be made

c i r c u i t voltage across the ohmmeter test

at points other than at the test jacks require the use

leads. Do not use the ohmmeter if the open

of an extender board (fig. 3-6). The extender board

circuit voltage exceeds 1.5 volts. Also,

is designed so that 11 connections are symmetrical-

since the RX1 range normally connects the

ly placed on each side of center. Because of the sym-

o h m m e t e r internal battery directly across

metrical design, insertion of the extender board

the test leads, the comparatively high cur-

right side up or wrong side up will not mechanically

rent (50 ma or more) may damage the tran-

or electrically affect the circuit. However, p l u g - i n

s i s t o r under test. As a general rule, the

b o a r d s inserted in the extender board must be in-

RX1 range of any ohmmeter should not be

serted exactly the same as originally positioned in

used when testing low-power transistors.

t h e equipment.

(3) Waveforms. Signals associated with digital

(6) Resistor, capacitor, and diode color code

circuits are illustrated with waveforms, Unless

diagrams. Color-code diagrams for resistors,

o t h e r w i s e specified, pulse duration is a secondary

capacitors, and diodes (figs. 8-0.1 and 8-0.2) pro-

consideration, Important pulse durations are speci-

vide pertinent resistance, voltage rating, and toler-

fied as nominal values when applicable. Test point

ance information.

pulse amplitudes are not shown, since they all range

between 7 and 12 volts. Waveforms shown for the

CAUTIONS

transmitter output specify all characteristics of the

Make sure that no metal objects (screw-

p u l s e s except the levels, which are determined by

d r i v e r , pliers, etc.) come in contact with

power measurements of the transmitter output.

the printed circuit board while power is ap-

NOTE

plied. A short circuit of the wiring could

When pulse duration is specified, it is

damage the solid-state circuit elements

measured between the 50-percent points of

mounted on the board.

t h e waveform. Pulse spacing is measured

Be certain both the extender board and

between the 50-percent points of the lead-

plug-in board are properly installed in

ing edges of the specified pulses.

their respective sockets.

(4) Test points. All electrical subassemblies of

3-3. Test Equipment and Tools Re-

the test set are equipped with test jacks to facilitate

quired

c o n n e c t i o n of test equipment (para 3-4 b). These

test jacks should be used whenever possible to avoid

The following chart lists the test equipment (a

needless disassembly of the equipment. The test

below) for general support maintenance of Test Set.

points are shown on the schematic diagrams. Figure

Transponder AN/APM-123(V). The associated tech-

8-36 illustrates the waveforms for certain test

nical manuals are also listed. Tools are listed in b

points. Physical location of the test points is shown

below.

i n figure 3-6. Test point (TP) numbers are color

CAUTIONS

coded and can be identified by the standard

M a k e test equipment connections care-

RETMA color code as indicated in the charge below:

f u l l y to avoid short circuits that can be

caused by exposed test equipment connec-

Test point

tions. Tape or sleeve test probes or clips, as

Test point color

number

necessary; leave only sufficient metal ex-

Brown. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

posed to make contact to the circuit under

Red . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Orange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

test.

3-2