Re: NO SPARK....ignition coil???
You can check the condenser with a capacitance meter.
Here is a little light reading about what that little thing does...
The main purpose of the capacitor "condenser" in points and coil ignition system is to both slow the buildup and collapse of the field in the coil and to cause a "damped oscillation" to take place in the coil when the points open.
What happens is that when the points close (and short out the capacitor), a strong magnetic field very quickly builds-up in the primary circuit of the coil. Incidentally, a small and insignificant spark is produced when the points close, similar to the spark produced when they open when there is no capacitor in the circuit.
When the points open (and un-short the capacitor), the field in the coil collapses and the counter emf generated by the collapsing field charges the capacitor. The resistance to a changing voltage that is characteristic of a capacitor slows the collapse of the field and this slight slowing of the collapse contributes to a more effecient coupling of energy to the secondary (high voltage) winding of the coil.
The damped oscillation (otherwise known as a "ringing oscillation") is caused when the field pushes energy to the capacitor then, after the field has collapsed, the capacitor pushes energy back to the coil rebuilding the field somewhat. This happens several times until the energy dissipated by the high voltage sparks has used up all the primary energy that was dumped into the coil when the points were closed. Usually, about 4 or 5 cycles of charge/discharge occur before the energy poops-out and this all happens within about 1/1000th of a second so what you think is one nice hot spark is actually several less energetic sparks all occuring in a very short time.
Another way to describe a damped oscillation is to liken it to the striking of a bell. When struck, the bell vibrates at what is called it's "resonant frequency". This is the frequency at which the bell shape is happiest at vibrating at and, naturally, the bell rings much louder at this frequency than at any other. In the coil-capacitor circuit, the two components make an electrically resonant circuit so the coil "rings". When it rings, it does so very loudly, hence the big, fat spark when it's happily resonant.
So, when everything is working right, the capacitor does several things, (1): The capacitor slows the first field collapse and build-up after the points open, causing a better energy transfer and a hotter spark, (2): The damped oscillation gives several of these hotter sparks and, (3) because the voltage rise uopn the opening of the points is slowed by the capacitor, the points can open faster than the voltage rises, keeping arcing to a minimum.
As a note, points will arc even with a capacitor across them if they are opened very slowly. That's why the cam ramp for point-and-coil ignition on slow engines must be very steep if they are to run well at low speeds.
