Topics: 6May 14, 2015 at 3:23 am #1486
I got a couple of these Atom computer ignition modules in a motor I junked a while back and got to use them recently.The first motor I put one in (a 1974 2hp Johnson) never has run well and it was out of desperation I tried this part .It starts ,runs and idles like new now .That prompted installing the second in an old Japanese motor that has no spark and no part availability .It has some spark now but not enough to fire so I’m wondering if there is anyway to boost this kind of ignition.Any ideas?May 14, 2015 at 3:25 am #15908
If you can supply manufacturer’s data sheets or manuals for that hardware, it would be helpful for those of us without direct, personal knowledge of the system.May 14, 2015 at 5:57 am #15921
If you want to read up about them Google US Patent 4,163,437 Aug 7 1979. If you want the actual circuit of them with component values to make your own then ive got them, as ive reverse engineered one. There is nothing computer about them at all. Theres 3 resistors, 1 capacitor, 2 transistors in them. On the motor that you have a weak spark try reversing the polarity of the module, also the condencer needs removing as its not required.May 14, 2015 at 6:44 am #15922quote debe:
I’d be interested in a schematic. Could you post it?May 14, 2015 at 6:53 am #15923
Unfortunatly unable to post on this site. Could email it if you PM me.May 14, 2015 at 7:06 am #15925
The red modules are for outboards with adjustable timing while the purple ones are for motors with fixed timing. Atom made their modules color coded for different applications in all kinds of magneto equipped motors.
My ’40 Zephyr and ’60 McCulloch both have the red ones in them and it’s like night and day as far as easier starting and smoother idle compared to the points ignition are concerned. If they were still available, I think I’d change all of my motors ignition systems to the Atom modules. I still have four new ones and I think that was the last of them from Banta Saw.
I won’t even talk about the Nova II’s.
Here’s one Debe took apart.
US Member - 1 Year
Topics: 20May 14, 2015 at 10:57 am #15933
Is there still a source for Atom’s?May 14, 2015 at 11:23 am #15935
You may find some old stock as production ceased in 2005. They used to sell for $28 here in Australia.May 14, 2015 at 3:33 pm #15951
Here’s Debe’s pictures showing a schematic, materials, and assembly of his module. Mighty fine work!May 14, 2015 at 6:34 pm #15955
@Dede / Mumbles
That’s brilliant, thank you both. So let’s take a moment for theory-of-operation..
Correct me if I’m wrong, but this module triggers off of the rising voltage waveform induced across the ignition coil primary? I just can’t see any other way it would work – there aren’t any magnetic sensors and the old points are gone, so they can’t be used as a signal.
How could you possibly establish correct +and+ consistent ignition timing with this? Ep is a function of dB/dT, so the faster the rotor spins, the greater the voltage induced by a particular angle of rotation. If the module is set to always fire at a particular level, this would mean that the timing would advance as the engine speed increases.. and that the base timing angle is affected by things like magnet quality, rotor/stator gap, rotor magnet/coil geometry, and on.
"With Unique Timing Adjustment" is right.. So how the heck does it work? :geek:May 14, 2015 at 6:46 pm #15956quote legendre:
How do they work? Really good! 😀
Someone in the past once explained how the different components in the different modules know when to correctly trigger the ignition coil. Hopefully they will see this and explain it again.
US Member - 1 Year
Topics: 157May 14, 2015 at 7:37 pm #15960
Mumbles have you made and used a Module from the above drawing? I priced the parts on Ebay and could build 10 for $40.49.
US Member - 1 Year
Topics: 157May 14, 2015 at 8:19 pm #15961
Mumbles did you build one of the Red modules from the drawing. I priced the parts on Ebay and I can make 10 for $40.49.May 14, 2015 at 10:04 pm #15969
If you go to Photo bucket debe5 there is a video of my home made module on a running Victa 2stroke lawn mower. Also pictures of my outboard with the module on to see if they worked & they do. If you want to go in to the theory of how they work, read the US patent refered to in a previous post. It has taken me over 2 years to find a suitable transistor (2SD1071) that would work in this circuit. I found on some Ignition systems the transistor would break down. To over come this I added the 15KE200A to reduce the high voltage spikes. This then made the module reliable.May 14, 2015 at 10:39 pm #15974quote mercuryman:
No, those are Debe’s pictures of his module.
That’s totally out of my league to try building something like that. Maybe I’d attempt it after eating a truck load of carrots and my vision improved. 😉
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