3. Observe the polarity of the 27.5 volt dc
Cautions:
power source. Polarity reversal may damage
1. The test set inverter is transistorized.
the transistors or electrolytic capacitors in
Use all precautions to avoid transistor dam-
the circuits. This equipment requires a nega-
age
tive ground. If a battery eliminator is used
2. Make test equipment connections care-
as the 27.5 volt dc power source, it must have
good voltage regulation and low ac ripple.
fully so that shorts will not be caused by ex-
posed test equipment connectors Tape or
Good regulation is important because the out-
sleeve (spaghetti) test prods or clips as neces-
put voltage of a supply that has poor regula-
tion may exceed the maximum voltage rating
sary to expose only the amount needed to
of the transistors in the inverter.
make contact to the circuit under test.
Section II. TROUBLESHOOTING PROCEDURES
(4) CONTROL TEST to 1.
2-4. Test Setup
b. Set the controls and switches on the con-
All bench tests of the test set require vari-
trol unit to the following position:
ous types of test equipment, depending on
(1) Function switch to OFF.
the particular test. To prepare the test set for
(2) BFO-OFF switch to OFF.
troubleshooting, perform the initial setup
(3) GAIN control to fully counterclock-
procedures described below.
wise.
a. Set the switches on the test set to the fol-
(4) Range switch to 190-400.
lowing positions:
(5) TUNE control fully counterclock-
(1) DC POWER to OFF.
wise.
(2) GONIO DRIVE to ON.
c. Connect the test set to a 27.5-volt dc
(9) RECEIVER-CONTROL to CON-
power source.
TROL.
Previous Page
