Figure 3-2. Test set, front panel component identification.

TM 11-6625-467-34

Figure 3-2. Test set, front panel component identification.

TOR switches where applicable. An X appearing in

3-7. Voltage and Resistance Measurements

the CIRCUIT SELECTOR switches column indi-

The normal voltage and resistance measurements

cates the position of the switch.

taken at the emitter, base, and collector of each

( 4 ) Special conditions for voltage measure-

t r a n s i s t o r are presented in table 3-2. Use these

ments are listed in the Other Conditions column.

measurements and the schematic diagrams to iso-

b. Resistance Measurements. The resistance

late troubles in the test set.

readings in table 3-2 were obtained under the condi-

WARNING

tions given in (1) through (4) below. Always make

Use insulated test probes when making re-

resistance measurements under these conditions or

quired voltage measurements. Always dis-

the readings obtained may be inaccurate.

connect the power cord from the test panel

(1) Make all resistance measurements with a

before touching any of the internal parts.

20,000 ohm-per-volt multimeter (AN/USM-223 or

Ground points of high potential to remove

equivalent).

residual voltage.

(2) Make all resistance measurements on the

a. Voltage measurements. The voltage readings

plug-in circuit cards with the circuit cards discon-

in table 3-2 were obtained under the conditions

nected from the chassis.

given in ( 1 ) through (4) below. Always make voltage

( 3 ) Make resistance measurements on the

measurements under these same conditions or the

chassis with all circuit cards in place and power dis-

readings obtained may be inaccurate.

connected.

( 1 ) Make all voltage measurements with a

( 4 ) Make all resistance measurements with

20,000 ohms-per-volt multimeter (AN/USM-223 or

respect to chassis ground or circuit card ground,

equivalent) unless otherwise specified.

w h i c h e v e r is applicable. make the resistance

( 2 ) Make all voltage measurements with

measurements with the negative ohmmeter probe

respect to chassis ground. Use the circuit board

connected to ground.

extender to extend the circuit card above the card

cage.

c. Table. The following table 3-2 lists the volt-

ages and resistance at the emitter, base, and collec-

(3) Make all voltage measurements with power

applied and the POWER SELECTOR switch set to

tor of each transistor in the test set. Unless other-

wise indicated, all voltage readings are positive de.

NORMAL. The CIRCUIT SELECTOR switch col-

The CIRCUIT SELECTOR switch settings and the

umn specifies the setting of the CIRCUIT SELEC-

3-6