no spark from cap

YOU GET SPARK from the coil?

How long? Blue? Red? snappy? weak?

If you get a good spark from the coil, FORGET the points and condenser for now

RECHECK the spark at the coil

Do this TWO ways, in order to check the coil wire

1 Devise a grounded probe, IE screwdriver and clip lead, or even a spare spark plug that you can "rig" for a gap. Hold the probe into the top of the coil tower and look for the quality of the spark. Most healty systems will jumper a spark with the probe held clear to the top of the coil tower.

You MUST use the key to crank the engine (instead of jumpering the start relay) because of the ballast bypass circuit OR you can "cheat................................."...............

To be able to crank the engine by jumpering the relay, which is obviously handier if you are alone, do one of two things-----either jumper the ballast with a clip lead, or hook a clip lead to the coil + terminal and to battery. A handy way to do that is from the coil + to the alternator output stud. Do NOT leave this hooked up any longer than for testing.

So the FIRST QUESTION after this test is

A Is the spark out of the coil OK?

B Is the spark weak?

A If OK, add the coil wire, and check the spark again at the end of the coil wire. Hey, coil wires go bad. If that looks OK, then Take a GOOD look at the cap, the rotor, for grease, dirt, moisture, cracks, carbon tracks, or physical damage, and pay attention, "was the cap seated properly" in the "key" on the distributor?

IF that seems OK, then test spark AT the cap at one or two different plug wire towers, using the same method as with the coil, IE a grounded probe held near/ into the top of the tower

B IF the spark is weak, then it's power supply, coil, points, condenser

So again, to make SURE you have power, jumper a clip from the coi + to the battery or alternator output stud, and check spark right at the coil

IF it is weak, it's either points, condenser, or coil.

Points and condenser are cheapest. Even if points are gapped correctly, they can be damaged, misaligned, and otherwise not making good contact.

You MUST have a good condenser. Condensers are NOT only to "keep points from burning." Condensers help form the spark, and MUST be good

The coil. This is a crap shoot. If you have a known good spare, does not take long to substitute. Yo do NOT need to even mount a spare coil, or even ground it!!! You can just "lay" it down there somewhere and hook it up!!!!