from wires and shielded parts, and conduct any radio frequencies to a grounded portion of the road roller.
99. Effect of Suppression
There is no interference from equipment satisfactorily suppressed for radiated and conducted interference over the
frequency range of 0.55 through 156.0 megacycles at a distance of 25 feet from the road roller.
100. Testing Suppression System
a. Install a battery-powered radio receiver in good operating condition not more than 10 feet from the road roller. If
possible, use a wide-band receiver covering the frequency range of 0.55 to 156.0 megacycles.
b. Start the engine and tune the receiver. Turn the receiver volume control to maximum, and select three widely
separated frequencies for listening. Use frequencies that are free from signals with strong carriers so that the receiver will
be in its most sensitive operating condition.
c. Operate the engine throttle, and listen to the receiver speaker or headset. A regular clicking sound, which varies
with engine speed and ceases the instant the ignition is shut off, is caused by the ignition circuit.
d. A whining sound, which varies with the engine speed and continues a few seconds after the ignition is shut off, is
caused by the battery charging genertor.
e. Systematically replace suppression components in the circuit causing trouble, testing after the replacement of
each component to see that the trouble has been eliminated.
101. Suppression Components
a. Battery Generator Capacitor. The battery generator capacitor (A, fig. 16) is mounted on the top of the battery
charging generator.
(1) Removal. Disconnect the capacitor lead, remove the mounting screw, and remove the capacitor.
(2) Installation. Install the capacitor on the battery generator and tighten the mounting screw securely. Connect
the lead with the capacitor terminal. Start the engine and check capacitor for proper operation.
b. Voltage Regulator Capacitors. The voltage regulator has two capacitors (B, fig. 16) mounted on the bottom part
of the regulator.
(1) Removal. Disconnect the leads, remove the mounting screws, and remove the capacitors.
(2) Installation. Install capacitors and tighten the mounting screws securely. Connect the capacitor leads and
start the engine. Check the capacitors for proper operation as described in paragraph 100.
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