A coil has two windings, the primary and secondary. The primary current is controled by the ignition, points or electronic. The ignition turns the coil on, while on it builds a magnetic feild around the secondary. When it gets turned off the magnetic feild collapses, this create current flow in the secondary windings. This curret is what make the spark plugs spark.
Check the resistance from plug cap to plug cap. It should read 23K ohms. The book states just the coil ohms, the caps add 5K each, 10 total + the 13k from coil = 23K These readings can vary + or - 20%
The primary side should be around 2.5 ohms. + or - 10%. Also check from the primary side to ground, and from the plug caps to ground. Should be infinity.
The pick up has two coils inside, both should read 700 ohms. Check from the black wire to both of the other, green and red often have a white tracer.
If all these checks are ok then the TCI box is most likely the culprit. It is a black box about 3-4 inches square and 3/4 to 1 inch thick. It is mounted to the bottom of the battery box. 6 or 7 wires coming out of it.
Some people have had luck fixing the TCI box by resoldering all the solder joints, Replacing the transistor can sometimes work.
Getting another TCI box can be a crap shoot. It may or may not work. If it works it may work for a long time or not.
There are lots of options if your TCI box is bad. There are many electronic ignitions out there. You can even convert to points.
I use and greatly like the Pamco ignition. Not too expensive, easy to install and has several options on the kits. Different coils vary the price. Mike's has the kits. To convert from the TCI too the Pamco you need a kit that has the advancer parts.
