First ensure all wires to the primary circuit from the battery through the coil, points to ground are in good condition including their connections (clean the contacts of the points with a fine emmery board or emmery paper). Ensure the points are set with the correct point gap when open as per specs.
Make sure the POLARITY is correct on the primary coil connections + to battery - to the points, a coil will operate when hooked up backwards at a reduced voltage output and a reversal in secondary polarity also. (voltage to the points when they are OPEN should be 12v minimal on a 12v system,(6v on a 6v system) with ignition switch in the ON POSITION OF COURSE).
To test a condenser correctly you will need a high cost oscilloscope. Just replace the condenser, they are cheap.
A coil output test is the sure way to diagnose a failing coil. O-scope again is the best method, however, once you have ensured the primary circuit is okay. You can measure resistance of both the primary and secondary windings of the coil with an ohmmeter and compare to specs. Measure the resistance of the coil wire also to eliminate the possibility that the coil wire is defective.
A Dynamic test can be done as follows.
Remove the high tension lead from the distributor CAP and hold this lead close to a clean engine ground (1/2 inch away). With ignition switch on, and engine being cranked, you should see an intermittent "bright blue spark". An orange or yellow spark indicates low voltage.
REMEMBER the secondary circuit can ONLY work as well as the primary circuit will allow. Don't condemn the coil until you are sure that the primary circuit is functioning at the correct voltages.
If a good bright blue spark is observed, check the spark at each plug in the same manner. If the sparks differ (yellow/orange at the the plug leads) then you have either a) defective plug wires b)defective distributor cap c) defective rotor
BY THE WAY,the distributor dwell angle determines the saturation level of the coil, the condenser controls the rate at which the magnetic field collapses within the coil. The amount of voltage delivered from the coil is dependent upon secondary circuit resistance.
Therefore, distributor timing will in NO WAY affect the amount of voltage delivered by the secondary circuit. Timing means "TIME" not amount.
