Heck, I don't know whose post I was replying to but that's nothing new either!
I thought I had read somewhere on AS that the laminations inside the coil would dry out from excessive heat and that was one cause of the coil failures. But, I could be remembering it incorrectly or maybe what I read was wrong too?
Either way, I wonder if there are multiple issues with those coils. I know here in southern Az that we frequently have humidity levels in the single digits and dew pionts in the negative numbers. We'll also get many weeks between measurable rainfall. All this makes me wonder if it's moisture that has caused coils to fail for me?
However, whatever the cause is, I'm grateful that there's a way to bring some of those coils back to life.
Great shared info and discussions on this Pioneer thread. Thanks to all those that help and share.
I think of the coil sort of like a transformer. The laminations create a rising and falling magnetic field as the magnets pass under it. That field cuts a wire coil and generates an electric charge.
In my opinion, the laminations would do their job even if completely immersed in water or in a vacuum (absolutely no moisture). I'm guessing the Prestolite coil contains a transistor that is wired in a way to inhibit discharge until one of the magnets triggers that discharge. Any moisture could upset its ability to build a charge before discharging. There are other solid state methods of building to a specific voltage level before discharging, water would also inhibit their ability to build an electric charge.
If there is any airspace within the insulating material of the coil it could conceivably condense moisture into a very small amount of water. Again IMO that's all it would take to cause the coil to not charge.
I am not nor do I claim to be an electrical engineer.
Quick transformer lesson. A transformer contains 2 coils of wire, joined by a laminated core. The input side generates a magnetic field in the laminations that induces a voltage in the second coil of wire. With few exceptions, there is no electrical connection between the two coils of wire.
My FarmSaw grew up in New Mexico, probably less humid than is Arizona (I have 8 years in Phoenix). Since 1991± its been in Washington State. Arguably one of the wettest states in the union. Until the GTG and I stored her on the ground I didn't have an ignition problem.