ignition module
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From: dcaster on 16 May 2010 22:07 The ignition module on my chainsaw ( Craftsman 358.350180 made by Poulan Beard ) failed. Naturally it is a potted unit and the easy thing is to just get a new module. But inquiring minds want to know what are the parts in an ignition module and the theory of operation. Anyone know? The internet had lots of articles on how to test, but none on what is in the module or how it works. At least cursory searching did not find an article. Dan
From: Robert Baer on 17 May 2010 03:54 dcaster(a)krl.org wrote: > The ignition module on my chainsaw ( Craftsman 358.350180 made by > Poulan Beard ) failed. Naturally it is a potted unit and the easy > thing is to just get a new module. But inquiring minds want to know > what are the parts in an ignition module and the theory of operation. > Anyone know? > The internet had lots of articles on how to test, but none on what is > in the module or how it works. > At least cursory searching did not find an article. > > Dan Good old flyback system. Look up transistorized ignition or something along those lines...
From: Robert Roland on 17 May 2010 09:27 On Sun, 16 May 2010 19:07:12 -0700 (PDT), "dcaster(a)krl.org" <dcaster(a)krl.org> wrote: >But inquiring minds want to know >what are the parts in an ignition module and the theory of operation. There are a few possible options. My guess is that it is a CDI (Capacitive Discharge Ignition) unit. It uses a high-current capacitor and a thyristor. If you google it, you'll find more info. -- RoRo
From: Michael Robinson on 17 May 2010 11:51 <dcaster(a)krl.org> wrote in message news:ff3a4d8c-1694-4145-93ee-9f54a10df83d(a)v18g2000vbc.googlegroups.com... > The ignition module on my chainsaw ( Craftsman 358.350180 made by > Poulan Beard ) failed. Naturally it is a potted unit and the easy > thing is to just get a new module. But inquiring minds want to know > what are the parts in an ignition module and the theory of operation. > Anyone know? > The internet had lots of articles on how to test, but none on what is > in the module or how it works. > At least cursory searching did not find an article. > > Dan Can you link to some of the testing how-to articles? Can you find out what kind of sensor triggers your module: magnetic, hall effect, optical? For what it's worth, the module itself surely has a high-voltage semiconductor (perhaps an IGBT or an SCR) and ancillary circuitry. I'm guessing the ignition coil itself is a separate part and not contained in the potted module. The aforementioned sensor detects the moment when the piston is positioned for firing and sends a signal to the module. The module fires the ignition coil in one of two ways, either the dwell method, or by dumping the charge from a high voltage capacitor into it. Sorry I couldn't be more specific, but I don't know much about chainsaws.
From: dcaster on 18 May 2010 09:06
On May 17, 11:51 am, "Michael Robinson" <nos...(a)billburg.com> wrote: > Can you link to some of the testing how-to articles? > Can you find out what kind of sensor triggers your module: magnetic, hall > effect, optical? > For what it's worth, the module itself surely has a high-voltage > semiconductor (perhaps an IGBT or an SCR) and ancillary circuitry. I'm > guessing the ignition coil itself is a separate part and not contained in > the potted module. > The aforementioned sensor detects the moment when the piston is positioned > for firing and sends a signal to the module. > The module fires the ignition coil in one of two ways, either the dwell > method, or by dumping the charge from a high voltage capacitor into it. > Sorry I couldn't be more specific, but I don't know much about chainsaws. The ignition module has a high voltage lead to the spark plug. A terminal that the kill switch connects to, and a ground terminal. It is situated about .030 inch away from the flywheel, which has embeded magnets. There are no points or separate sensor for flywheel position. It may or may not have a capactor or some sort of semiconductor in the module. There is no separate ignition coil. The testing links just say disconnect the kill terminal , pull the spark plug, and pull the starting rope while observing the spark plug. If there is no spark , the module is bad. Replace module. If there is a good spark, then hook up the kill terminal and see if there is still a spark. No spark , then the problem is in the kill switch. I suspect there could be a 4 layer diode in the module. But that is why I am asking if anyone knows. Dan |