Service Manual

Part Numbers
59-1180
Purpose
The condenser (or capacitor) protects the trigger module.
How It Works
In order to get the spark plug to fire, about 20,000 volts must be present at
the plug. This is accomplished by using primary and secondary windings
in the coil. The primary is low voltage while the secondary is higher
voltage. However, by themselves neither can produce 20,000 volts. A
trigger module is necessary to turn the primary on and off. By quickly
turning the primary off, a 20,000 volt “spike” is created in the secondary
which fires the plug. What does this have to do with the condenser?
The turning on and off of the primary can be hard on some of the
components in the trigger. The condenser (capacitor) lowers the “spikes”
seen in the primary and enhances trigger module life.
Testing
There is really no way to easily test this .3 micro farad, 200 volts A.C.
capacitor. However, if you have experienced a trigger module failure,
replacing the condenser is recommended because of the nominal cost.
Part Numbers
78-1630
Purpose
Converts alternating current into pulsating direct current and prevents
battery current from feeding back through the alternator.
How It Works
A diode is merely a one-way valve for electricity. Coming straight from the
alternator, the current is half positive and half negative as shown in
diagram “1" at left. The diode ”filters" out the negative half of the wave to
give you the waveform you see in diagram “2". Why then does your VOM
read a steady direct current when you check the output? The reason is that
the meter is designed to read an average voltage when the current is
rapidly changing.
When you read 14 volts, keep in mind that the peak voltage is closer to 20
volts. IMPORTANT: The silver band must be oriented as shown in diagram
3. Otherwise, current will feed back through the alternator.
Testing
1. Disconnect the diode assembly from the wiring harness.
2. Check terminals “a” and “b” for continuity with a VOM. Note the result.
3. Reverse the VOM attached to “a” and “b” and again note the
results. You should have found continuity in one direction, but not the
other. If not, replace the diode assembly.
Condenser
(capacitor)
Diode
(replacement kit)
Glossary
GLOSSARY
3-8 Demystification Guide