ATOM Diy module

[tysman]

i took apart a blue electronic coil only to find 2 components a 1479c transistor and a 203yy SCR i dont see any resistors

 

[tysman]

found the d1071 on ebay, is the mosorb to protect the module which makes it better then the nova which burnt out sometimes?

 

[debe]

Yes the Mosorb is to protect the module. Heres whats in the blue Atom module

 

[tysman]

ok i wonder whats in the yellow module. it seems to not do much more then the brown

 

[large_ghostman]

Fantastic, just like the old ETO bodger posts! I hate the buy it for $1 on ebay stuff, I like the take it it apart and copy stuff . I have also saved this for the future........

 

[tysman]

what colour module would I use for lawnmowers, rotor tillers like Briggs?

 

[debe]

The listing gives a Green module for Brigs engines.

 

[debe]

This is a picture of a Green Atom ignition module used on Brigs engines. They are not my pictures & the person I got them from did not check any values. But the construction & transistors are the same as a Red module. Personaly I would build the Red module & just try it on a Brigs engine.

 

[tysman]

ok thanks, I wonder whats in the original transistors of the ATOM and Nova? they don't seems to burn out after few minutes wonder how they can handle the spikes

 

[debe]

The transistor is marked A3 & has a Texas instruments symbol on it. So it was probably custom made & there order would have been in the thousands at the time. It has taken me several years to find a suitable transistor. Some of the criteria was suitable Gain, Current & voltage rating & it had to be a Darlington transistor. The MOSORB was added as a Wipac coil on Seagull outboards was very destructive to these modules & the Transistor.

 

[large_ghostman]

You wouldnt think it was so hard to do! You have done well to find replacements, I have a very old outboard on my little boat (Honda 75 engine). I might go take a look at it, although it needs alot of work before it sees water again!

Once I have a driving license I might have an incentive to get the boat finished .

 

[dr pepper]

British seagull, a blast from the past, was it the 40+ that had a brass fuel tank and villiers carb.
The coupling between the lt and ht side of the coil was probably poor, causing high voltage Rf.

 

[debe]

I have several Seagulls, This is a pic of the Modified 40+ with a Wipac ign used for bench testing of modules before seting them in resin. I use an electric drill to drive it. Also a module temporay fixed to a 5HP Tohatsu for sea trials.

 

[tysman]

Nice motor I have one more question and its about the bc337 on your module its hard to see how its soldered to the tranistor are all three soldered to each of pins of transistor? and which way does bc337 go?

 

[debe]

The center lead of the bc337 is turned up on it self.

 

[tysman]

ok and the middle leg is soldered to resistors and other end of resistors go to either side of transistor? what connects to middle leg of transistor?

 

[KeepItSimpleStupid]

The ST901T might be worth looking at: https://www.st.com/en/power-transistors/std901t.html

Here (non-Atom) https://docs.google.com/viewer?url=patentimages.storage.googleapis.com/pdfs/US5058543.pdf is a more complex patent that adds temperature compensation to make starting a hot engine easier.

 

[debe]

The ST901 is probably worth a try, I wont be as I have plenty of the 2SD1071 transistors. Hope the makes it simpler for you.

 

[tysman]

That's perfect thanks lot easier

 

[KeepItSimpleStupid]

This https://media.digikey.com/pdf/Data Sheets/ST Microelectronics PDFS/2ST501T.pdf guy has an Hfe of 2000.