eightfifty wrote:
It's an interesting video and well presented, but in my opinion, he's actually got it wrong. At 3:59 he says "there's no light there because the points are open". (he's talking about the "electronic" points in the "igniter" module). Since he's connected the test light to the points side of the coil (and the other end to chassis ground), then surely there is no light there becase the points are closed - not open. When the points open, there will appear 12V at the points side of the coil and so the test light will light.
But, you have to be careful with this. Because this is an inductive circuit, the instant the points open, there is a huge kick voltage generated at the CB terminal of the coil (up to 400V) or so which will damage anything sensitive connected to this terminal (like an oscilloscope or voltmeter). It doesn't much matter for the guy's test light although it might burn out if it's resistance is too low. Automotive test equipment accounts for this, but ordinary Jaycar equipment will not handle it.
It's surprising he doesn't mention the most commoin failure of these devices, and that is, heat. The "igniter" (nice sales terminology) has a transistor in it capable of switching a substantial amperage, but like all electronic devices, is not 100% efficient and the heat generated has to be disipated. If you've ever looked at a car radiio of the period, you can see the power transistors are always large metal-cased items screwed to the chassis (but insulated with mica washers) for the same reason. For these electronic distributors, there is hopefully a small amount of heat conductive grease supplied which is applied to the base plate to reduce heat build up. Sometimes the "igniter" comes good again once it cools down which makes it difficult to find the fault.
If that is how it is connected you are correct (I haven't rewatched).
Really all the testing in the video is identical to points ignition and is only a basic test.
Early electronic ignition modules had decent sized heatsinks to dissipate the heat and prolong the component life. Newer electronics are more efficient so generate less heat however I still believe it is a bad idea with how they rely on the distributor base as a heatsink. There is no airflow and a small mass. I avoid any electronics in an engine bay, heat decreases component life dramatically and add to that the fact that a lot of modules are made cheaply.
