Each of the following locations should contain a capacitor:
1. On the positive terminal of the ignition coil.
2. If a generator is present, on the armature terminal of the generator.
3. If a generator is present, on the battery terminal of the voltage regulator.
Most alternators are equipped with an internal capacitor to eliminate what is referred to as "whining" when the engine is revved. If whining is audible in the radio, or simply to be extra cautious, a radio interference capacitor can be added to the battery terminal of the alternator.
It is also crucial that the battery lead is in good condition and that the ground leads are not compromised. A robust ground connection should exist from the battery to the engine block, along with additional grounds to the body and chassis.
Failure to observe these precautions may result in voltage spikes on the battery leads. These spikes originate from ignition systems, charging systems, and from toggling some of the vehicle's other systems on and off. Modern computer-operated equipment can be particularly sensitive to voltage spikes on the power leads, potentially leading to unexpected resets, unusual behavior, and/or permanent damage.
Vintage Air endeavors to fortify our products against these types of electrical noise; however, there is a threshold beyond which a vehicle's electrical system can deteriorate to the point that no remedy is effective.
Radio interference capacitors should be readily available at most auto and truck parts suppliers. They are typically cylindrical, measuring just over an inch in length and slightly more than half an inch in diameter, featuring a single lead extending from one end of the cylinder with a terminal at the end of the wire, as well as a mounting clip that is secured to a reliable ground on the vehicle. The specific capacitance value is not particularly significant when compared to ignition capacitors that are paired with the coil to minimize pitting of the points.
Caution must be exercised when installing the components.
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