Another economically made module from the wiring loom of a Chinese quad ATV or scooter.
This module interfaces between the magneto/alternator and the ignition coil to provide high current pulses in sync with the engine.
The use of a high voltage winding on the alternator/magneto is to store as much energy in the 1uF capacitor as possible for dumping through the ignition coil in pulses to induce a high voltage spark.
It's a very simple circuit, but this one has some odd quirks compared to others.
Is the input RC arrangement to provide a speed dependent timing variation for the spark?
Is it normal to short circuit the high voltage winding of the alternator on each alternate half wave?
Anyone had a shock from the appropriately named "kill circuit" on the keyswitch or engine switch?
Let me know what you think in the comments.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
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This module interfaces between the magneto/alternator and the ignition coil to provide high current pulses in sync with the engine.
The use of a high voltage winding on the alternator/magneto is to store as much energy in the 1uF capacitor as possible for dumping through the ignition coil in pulses to induce a high voltage spark.
It's a very simple circuit, but this one has some odd quirks compared to others.
Is the input RC arrangement to provide a speed dependent timing variation for the spark?
Is it normal to short circuit the high voltage winding of the alternator on each alternate half wave?
Anyone had a shock from the appropriately named "kill circuit" on the keyswitch or engine switch?
Let me know what you think in the comments.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.
Hello,, what type of solvent did you use?
very nice, thank you a lot.
What is the solvent you used to extract the circuit board?
A few things to add here.
You have to thank Honda for the awful color scheme of those wires. That's how they color coded their wires in the 80's. Green is ground and black is switched positive. Of course, the Chinese copied that color scheme and it is still widely used in modern chinese motorcycles today.
The weird circuitry in the gate of the thyristor as many have mentioned is for timing advance at mid range. There are a few variations of this. Most notable one is the variation that delays the spark at higher rpm's, used primarily in two stroke engines. It just has a small capacitor in series with the sense coil.
Finally, there're two main variations of these cdi boxes. The ones based on an external AC input like this one. And the ones that receive 12 volts and have a small flyback transformer inside that elevates voltage to about 300V. I've been interested in what's inside of those. Hope you can reverse engineer one of those someday.
Small edit. Another notable example are the old Suzuki 2strokes that had a cdi/coil that worked out of only one power coil. On the positive half cycle it charged the capacitor and on the other half cycle it triggered the thyristor. Really clever design.
What component fails. So often in these cheap chinese scooter cdi units?
Possible timing advance at higher rpms?
Buena enseรฑanza.
ยฟLogrรณ conseguir el esquemรกtico de un CDI para moto 150cc alimentado a Baterรญa?
Para no usar la bobina de arranque del estator, sino usar como alimentaciรณn la baterรญa.
Hi Clive.. The ignition switch is based on Honda's wiring colours.. so red is battery and black is live after the the main switch..
I believe the extra unexplained 10uf capacitor is possibly for timing advance. Not all of the standard black box Chinese have timing advance though one. I bought one off Amazon and did not have timing advance while the one that came with my pitbike did, while still looking the exact same on the outside
Can i use this for 4stroke 250cc cg engine?
Sorry, the term quarter? scooter is unfamiliar to me. Anyone care to elaborate?
well explained. input capacitor filtering to allow only trigger signal. resistor devider to adjust igbt gate volt spec. Also may be freewheel diode can have small series resitance to limit max current of freewheel diode
i used piaggio scooters and their cdi units are known to fail . i had a piaggio typhoon and piaggio zip same problem and i bought a chinese motorcycle 110cc with that same cdi box and it has 76 k km no issues so far.
Hey I need some help with a project. Trying to run 2x of these on a dual cylinder build. Both coils always fire! No matter which cdi is triggered any ideas?
I took mine apart too, It was an older model and it even had some potenciometers in it. Engine run very well till, I got a short from too much water:D
The sand is a heat sink for the triac often it's ground ceramic material
What chemical was used to dossolve plastic case?
how about the dc cdi?.