CDI - Teardown via Picture, wanna help?

[DuctTapedGoat]

So, this is what I'm trying to disassemble with a pic. I can't see every component, and I would really appreciate some help in it.
It's a CDI for a motorized bike, and he wants 75 bucks for it. It's not patented, and I don't want to blow 75 bucks on something that's only 10 bucks in components. Anyone willing to help me diagram it out? It's simple enough, but some I just can't read.

[frenulem - No.5417]

what is the function of this device? any more pictures?

[DuctTapedGoat]

Short form, adjusts the spark on a 2 cycle motor.

Here's more info out here from the horses mouth. This isn't a picture I took keep in mind, it's one off his site under installation instructions. And it's the only one I can find.

http://www.dragonfly75.com/motorbike/CDI.html
http://www.dragonfly75.com/motorbike/CDI2.html
http://www.dragonfly75.com/motorbike/CDIinstall2.html
http://www.dragonfly75.com/motorbike/4curves.html

[frenulem - No.5417]

right so this is obviously not a PCB, just Veroboard/stripboard/whatever you wanna call it, the first thing is working out which way the copper goes

[hyper999]

I dont think this is stripboard i think its matrix board ( Like This )

or one of those ones with pads in groups of 3 holes or some variation on this, which makes reversing it from the picture very difficult...

[DuctTapedGoat]

I don't think so -  the diode and resistor by jumper/header A almost looks like you can see the wire through it, that or it's a scratch, but I think it's just cheap bread board.

[frenulem - No.5417]

Time to put this mofo into paint, it says the C106D is a thyristor, looking up the datasheet now

[hyper999]

I think your best option is maybe to buy one, reverse engineer it, then sell a couple to make your money back...

EDIT: Is this the same?

[frenulem - No.5417]

yeah, thats easiest, you dont know the values of somethings

[DuctTapedGoat]

It's another CDI box - but should give enough similar values to be able to process of elimination it out, at least with the resistors.

I'm near tempted to, but 75 before shipping is a lot of money even to start it out with. Gotta register for college when I get paid, and getting all that rolling is going to eat into my check a bit.

[hyper999]

so the one i posted doesn't function the same?

[DuctTapedGoat]

Nope - the xt600 was a 4 cycle motor, they fire completely different from a 2 cycle motor unfortunately. It functions relatively the same in that it's designed to discharge the capacitors in the coil to get spark, but with a different circuit sequence.

[FOOKz™]

I agree to just buy one and reverse it.

I did the same with a CFL bulb's internal PCB and breadboarded it just because I could and it was a cool idea.


Sir, i think you have yourself a bridge rectifier in there and a Logic-Level Thyristor SCR.

so when the voltage is switched positive it stays positive, when the voltage is switched negative it turns off.
I don't know much about small engines, but if that kinda makes a bit of sense of what the circuit can do. hyper's link to explain the relationship of the stator and ignition systems show why this is important, just timing.

I guess that this circuit just fires a pulse to the spark plug when the alternator is at a certain point?

what do you guys think

[DuctTapedGoat]

Exactly what it does. Essentially this one specifically is designed is to adjust the RPM's powerband as revolutions increase, and with a capacitor upgrade on the ignition coil, have a stronger spark.