ORIGINAL: gr8flyer55

Hi Rob..
I finally have time to post the ''How To'' for the toroid coil on the CDI boards.

I start by taking a 1/8'' wooden dowel rod cut to 1 foot in length to use as a shuttle for passing thru the center of the toroid. I cut a V-notch in both ends to keep the wire on the dowel as I prepare the wire. I usually wind about 30 turns of #36 guage wire onto the shuttle which gives me 30 feet of wire for the secondary winding on the toroid. This can be seen in the first picture. I wrap a 1/8'' slice of masking tape around the toroid on the perimeter which I trap one end of the wire to start winding so it won't slip. Leave about 1'' of wire hang out from the core to solder to the board when you are finished.
Proceed to wind in a clockwise rotation, keeping the turns close together. The next picture shows some turns on the core. As you wind the secondary, try not to loop the wire or get any kinks in it which could cause broken wires or cracked insulation and a shorted pair of turns later.

On the first layer around the toroid, I can get approximately 150 turns of wire, keeping it snug and without too many gaps in the windings. Take your time and take a few breaks now and then, writing the number of turns down so you can resume with a correct count of the turns. The second last picture is 400 turns of #36 wire on the core which completes the secondary windings. Wrap a strip of tape around the perimeter again trapping the last loose end of the wire, then trim it to about 1'' again.

The primary is wound next with #26 guage wire with 15 turns and taped again so it doesn't unravel from the core. Trim both ends of this winding to about 1''.

Next is the feedback winding from #36 wire for 6 evenly spaced turns around the core. Make sure you wind all turns in the same clockwise direction and keep them neat. When all turns are wound, take an exacto knife blade and scrape about 1/8th inch of the insulation from each winding end for soldering later to your board.

When all finished, your coil should look similar to the last picture.
I hope this helps those of you trying to wind these little gems. Any questions, just ask...

John