Hot Rod ECU EMS

Built holder for boards from 2 shelf boards as laying them out on table was taking to much room.  Wiring was mostly to route power to each board. I left enough slack in wires so I could pull each board out to check it with a scope.  I was glad I did as I start to do system tests to see if everything was still working, I found I had moved pot settings and needed to reset them to match setting from my initial testing.  The scope shots in my test reports were very helpful in doing this. Hopefully with this setup I can just connect the coils to connection strip on the end and continue testing.  One thing I do not like is the 2n3055 mounted on the leg make that whole leg to be at +12 DC.  I need to do something about that.  I am still working though checking things, but I did find another issue I though I would report.  I started on the analog side and was working my way though resetting the pots and I am getting the results I expected after making the necessary adjustments until I got to the finally output to the primary coil.  Instead of the analog wave train I expect I kept getting a flatline voltage.  This is from the 2N3005 (Q4 in K9 the Voltage Amplitude Control circuit). I retraced the signal through the circuit, and everything matched until I got the final output instead of analog wave train, I got a flatline voltage. In my initial testing I did not have the output from the emitter of the 2n3005 connected to the switch and the last 1uF capacitor.  The capacitor is the cause of the flatline.  Remove it and system works.  With it in you can still move the voltage level up and down but AM wave is gone.  It does not make sense to have gone to all the work of creating the AM signal then remove it before sending it to primary coil. It is possible this capacitor was intended to smooth out the noise on the AM wave as it has a lot of noise, however if this is the intended purpose 1uF is the wrong value.  However, if you want to smooth out noise on a 12-volt source then it would do that. I am continuing to check the other boards that feed the 5KHZ side and have started to gather some of the material I need to make coils.  Looks like a should find the ferrite core first so I know what size and shape to make coils and bobbins. I know the dimensions for the areas for the wire but need to know size of hole inside bobbins. Pictures below.  Front and back of finished boards mounted power comes in on left through a 12-volt connecter and there 2 LM317s one for 10v and on for 5v that feed bus bars on back.  Common ground through out system.  Boards powered from the bus bars.  Bus bar on the right will connect to primary and feedback coils. The scope shots show the output of the 2n3005 with the one with capacitor in circuit and one with it removed.   This is the signal going to one side of primary coil.  The yellow trace is the 50Hz signal input used to create AM wave.  I have it on screen to provide a good sync for the scope.

Main reason I built Stan's circuits is to try to find out what that signal shape should look like.  Also I had several questions about how he did things.  Where was gate generated?. How did he create the AM wave and what did it look like?  Where did he created the  high frequency pulse train? How did he merger them all together.  Building his circuits and testing them has answered most these questions though with all the adjustments in the system I am still not sure what the exact signal should look like.  Still plan to do more testing to learn more. I sure Stan did not start with these circuits but built them base on other experiments and knew what wave shape he wanted them to output. He used parts that were available at the time. I plan to take a good look at work Nav did on AM signals and chokes to understand that part of system much better.  See his recent post on AM wave testing. My goal is mainly to understand and to give me something to do that I am interested in.  It has done that so far.Continued testing with check the High frequency side.  Verified boards are working and then checked inputs to both sides of primary coil.  Channel 1 Yellow is from Cell Driver K4 and Channel 2 Blue is from Voltage Amplitude Control K9 on Analog side.  Both scope probes are hooked up prior to diodes as I wanted to see input to primary coil.  At this point I am just using a 10-ohm resistor to provide a resistive load.  The first picture shows this test setup.  As there is are no coils in the system, I have hooked the output of K21 (G) back to what would be the input (H) to the board from resonance sensing pickup coil and Pulse Indicator Circuit K14 (black jumper in picture). I took three pictures of the signals with different gate settings.  Large gate, 50% gate and small gate.  Gate size was set using pot on Gated Pulse Freq. Generator (3). Last picture show the output when the Switch on the Voltage Amplitude Control board (K9) is set to “OFF” I would not pay to much attention to frequency listed as the scope locks on the gate pulse to determine frequency. It should also be noted that each of the signals is refenced to same system ground point.

SMALL GATE

Large Gate

Cell off with Sw on AM board

50 Per cent gate

After writing this and looking at screen shots the 2 signals look the same just at different levels.  I begin to wonder if something had happened to analog signal. So, I disconnected it and went back and rechecked output of board using setup I had used to check analog path.  I set scope for CH1 yellow to be 50Hz reference from K2 CH2 blue to be analog signal which was the triangle wave train, so it was working.  I then hooked it back to output strip but left CH1 hooked to 50Hz reference and got the following signals.  I again varied gate size on K3.  Switching off analog gave flat line.  This was the analog signal I expected to see.  Did not expect pulses on top but was glad to see them.   But they are there as all inputs to primary coil are hooked up including diodes. I am beginning to see why people say scope shots do not make a lot of sense.  Would not have seen the analog wave in this form if I had not changed scope sync reference.   Note:  I used same ground reference for all of these screen shots.

above picture Analog signal with small gate

Analog signal large gate

Analog signal 50 per cent gate

As using a separate sync source gave me such a good view of the analog signal, I decided to look at the pulse stream the same way.  I went back to K2 and tried all four switch settings on one of the other switches, the 500Hz output gave me the best view of the shape of the pulses.  Picture was taken at about 50% gate setting.  You can also see effect of gate changes in this view.  This was taken just before diode going into Primary coil like the other pictures above. At this point I am not sure what the output modulation frequency is as the gate messes up that reading on my scope.  I will need to go through K21 again and check center frequency I am sure it was changed when I mounted board and I have not yet tried to reset it.  In this testing I was check that all the boards worked together, and primary goal was to see what signals looked like at input to primary transformer. I think I did that.

Close up view of pulses with 500hx reference