I tried end to end with the xj box with no joy. going to try with this one. Your wiring for the cap is just what I had in mind.
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Old Brown
- Thread starter Team Junk
- Start date
I'm jealous of those windows. 
Nice engineering on the light support.
Nice engineering on the light support.
A good friend gave me those when he sold his house. Been waiting 10 years to put them to use.
How odd. I had it packed with me yesterday, enjoying the mild weather ridin'.
Scoping those trigger signals is the only way I can think of to figger this out...
Crap. Spiralling ever further into the rabbit hole. I guess if it is the sort of thing that you toss in your pocket to go for a ride then I guess I need one too. In my mailbox tomorrow.
It's supposed to warm up a little over the weekend. Hopefully I' have a better idea about the TCI pickup soon.
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Pocket size?! Those vacuum tubes must be tiny! 
Found a image of the GN250 rotor. The magnet looks like it covers the arc of the advance range. I'm thinking that a modified pickup coil that covers that same arc is going to be required for the advance to work. Or a rotor modified with a longer magnet. The coil seems easier.
GN250 rotor
GN250 rotor
If tying the two pickups together in series works (fingers crossed), they already cover the advance range we're looking for. If not, I've a spare pickup I'll sacrifice for dissection. If it looks like you can make this work, I'm all in.
My suspicion is that the coils in series are producing 2 pulses instead of one long one. The other thing is with the magnet. If the coil is only exposed to one pole of the magnet then the pulse is only going to be a negative or positive pulse. The later igniters expect a pulse that goes both positive and negative. The scope will help sort this out.
Well I went out to the barn today and hooked up the new gizmo.
Sadly have not figured out how to save waveforms.
So hooked up neg connector to the common and red to orange from pickup.
Got the expected sine wave. Positive then neg. Same from the other coil.
In series just as I expected there are 2 pulses. There must be some overlap between the to coils.
The advanced pickup full positive and then a smaller negative and then another muted positive and full negative from the retarded coil.
Looking at the waveform it looks like the advanced coil starts with a normal positive excursion and then the retard coil starts it's positive excursion while the advanced coil is still in it's negative pulse nulling out part of the first negative pulse.
The good news is that the positive pulse first is what the GN250 box is expecting according to the GN250 manual.
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Retarded coil output
Coils in series advanced coil positive
Series connection just adds neg pulse in front of the positive pulse.
Going out to barn to try wiring in parallel .
Coils in series advanced coil positive
Series connection just adds neg pulse in front of the positive pulse.
Going out to barn to try wiring in parallel .
Parallel connection.
I'm wondering about just using one pickup and attaching a small, thin strip of iron (or steel) long enough for the degrees of advance we need. Think the magnet would energize it throughout it's pass across the iron strip?
Not a bad idea Jim. I have read a lot of threads and other all the info I have been able to find and I'm convinced there has to be a solution to this problem.
I'm really glad to finally have a clear idea of what the signals look like coming out of the pickups.
I have a collection of igniter boxes to try. There is variation in the magnet sizes of the bikes they come from. At least now I can see the polarities involved.
I can recommend the little pocket oscilloscope. The probes suck but pretty amazing to have a pocket tool that can do what it does.
One of my boys is coming out tomorrow to help with the new building. Hoping to get old brown in the new building on the lift so I can do some more investigating. Supposed to be mid 60's tomorrow.
The ultimate garage built. Godspeed.
https://abcnews.go.com/US/daredevil-dies-homemade-rocket-crashes-desert-filming-tv/story?id=69157084
https://abcnews.go.com/US/daredevil-dies-homemade-rocket-crashes-desert-filming-tv/story?id=69157084
