Procedures for Testing Transistor Circuits-continued

test. Damage will result from any external volt-

ages which are applied to the ohms circuit of the

TS-352B/U.

b. If the equipment contains transistors, and

does not have an isolation transformer in its

power supply circuit, connect one in the power in-

put circuit. A suitable transformer is identified

by National stock No. 5950-00-256-1779.

c. Make connections carefully so that shorts

will not be caused by exposed test prod or clip

connections. Tape or sleeve (spaghetti) test prods

or clips to leave a little exposed as needed to

make contact to the circuit under test.

d. When the TS-352B/U is used for resistance

measurements on transistorized equipment, use

the RX100 range only. The negative lead of the

ohmmeter circuit is connected to the positive side

of the battery. The equipment battery (or its

equivalent) is recommended as the source of

power when servicing transistorized equipment.

Observe battery polarity. Polarity reversal may

damage the transistors or electrolytic capacitors

in the circuit. If a battery eliminator is used in

place of the battery, it must have good voltage

regulation and low ac ripple. Good regulation is

important because the output voltage of a battery

eliminator with poor regulation may exceed the

maximum voltage rating of the transistors in the

equipment being tested. A battery eliminator

with poor ac filtering will create a false indication

2-14