TZR250 3MA
Go to content

Understanding the behavior off the 3MA-CDI seems for a amateur like me a bid odd.
To go deeper in this, I have changed my setup and using a uncut CDI
Here a couple off steps with are (for now) interesting.

3MA-CDI is connected the same as a running engine. (using my testing machine)
Explanation off oscilloscope signals. (new setup)
-3 (Purple) Thyristor gate (electronic switch for discharging the capacitor)
-4 (Green) Ignition outgoing signal from the IC (Pin 22)
-6 (Yellow) Pickup signal (measured before entering the T2333)
-2 (Light blue) Ignition incoming signal for the IC (pin 13)
-5 (Dark blue) Firmware from iCP-12
The graphics are a bid tight, but needed to do that in order to see the Frequency

Everything lower than 60Hz the ignition pulse firing at the end off the pickup pulse (no delay at all)
You see it here 59,5Hz end pickup signal is same as firing point.

Next step is 60,10Hz and you see that the ignition point has moved.
My logical tells me that from 1800rpm the ignition curve starts working, all before that is hardwired in the CDI

Next Odd thing, the IC ignitionpoint is splitting up at 75Hz. (Not that it influence the ignition point it self as it is still firing at the start off the pulse)
At 74.3Hz the ignition pulse  (green) is a solid pulse

At 75,3Hz you see the splitting starts

At 76,3Hz you see the splitting is complete and it will grow further as rpm is rising
Last but not least
The dark blue pulse is coming from the iCP-12, its a bid off compared with the original oem ignition pulse in the lower rpm
It starts to get equal around 90 a 95Hz
And follow the oem ignition pulse until the end capacity off my testing machine witch is around 150Hz.

New update: 17-05-2016

Made a new setup in order to investigate the low RPM problem.
New setup:
As I have a two channel function generator, it was time to use both channels.
Channel One is connected at the 3MA CDI
Channel Two is connected at the iCP-12
The iCP-12 is now only connected at the 5V circuit from the 3MA CDI (it has no more incoming signals from the CDI)
Now I can measure the 3MA CDI in and outgoing signals and iCP-12 in and outgoing signals at the same time on the oscilloscope.
But the two units now work completely on there own, no interfering off signals

Its a bid difficult to see with all the wires but here I'm using the two channel function generator
The (test) Icp-12 can be seen just under the 3MA-CDI

High (small) pulse is given from the pulse generator and is the incoming signal.
Top: iCP-12
Bottom: 3MA CDI (now you can see that the T2333 is enlarging the incoming signal)
Her you can see that the iCP-12 is giving a delay from 3,7degrees
This is at 90Hz
Her the 3MA has a delay off 24degrees
Back to content