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Dinoplex AEC 101DA rebuild

Discussion in '206/246' started by dgt, Mar 22, 2017.

  1. Fred Winterburn

    Fred Winterburn Karting

    Jan 27, 2015
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    Lars,
    Not trying to be argumentative, but 10 to 20 kHz is quite easy to do with those transistors. They chose to do it that way for whatever reason. Perhaps it was simply because they found a ready made transformer that worked when they tried it. Most of the older CD ignitions of the era, and before this one came out, ran at frequencies higher than 5 kHz, at least the ones I have tested. The old Hyland that my father developed in 1962 ran at about 8 kHz using a small ferrite core. His later ones from about 1966 onward used a similar design to the Dinoplex power supply with an even smaller ferrite core and they ran at over 10kHz. Using the PNP counterpart (2N6609) to the 2N3773 I have built power supplies that easily run up to 18kHz with a small core.
    The fact that many Dinoplexes are still running strong years later does show that it couldn't have been that badly designed. Nice that it was made to be rebuilt too, unlike the later AEC 103. Fred

     
  2. DinoLasse

    DinoLasse Formula Junior
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    Sorry to hear about the mishap, Andrew. Hope you can recover some of the power tools at least. Good that the Dino parts stayed safe, though! / Lars
     
  3. DinoLasse

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    The circuit appears to be straight out of the 1960’s RCA Designers Manual, showing a power converter to produce 120V 60 Hz AC from a 12 V battery. The slow turn-on that you cited in the previous post was probably exactly what the RCA designers intended: Gentle on the transistors and producing an output closer to a sine wave than a square wave.
    The Dinoplex designers appear to have taken that circuit and scaled it up in frequency by a modest factor of 4 to 5. A very sensible and conservative approach, it seems to me. / Lars
     
  4. Fred Winterburn

    Fred Winterburn Karting

    Jan 27, 2015
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    lars,
    Without scoping that power supply to be certain, it will produce a square wave (or mostly square) with rather large leading edge spikes. The spikes are precisely what gives that type of circuit the ability to produce a sufficiently high secondary voltage as the battery voltage falls. The spikes are larger as the frequency drops with a reduction in supply voltage, thus helping offset the reduction in supply voltage. A different design would allow fast turn on and off times for the transistors keeping the inherent voltage drop as low as possible (for lower I squared R losses in the transistor), and also keep the transistors from conducting any longer than necessary in the saturation region of the transformer. If the magnetic field isn't changing with current, then it is wasted as heat in the windings and the external circuit including the transistors. The right type of core material to reduce the effect of the inherent switching spikes and correct winding methods are a much more complex subject than I would have thought a few years ago. Maybe computer programs can figure it out consistently, but I doubt it. Fred

     
  5. DinoLasse

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    Fred, I am sure that everyone has had enough of the two of us by now, so I promise this will be my last comment on this subject:

    No doubt it is producing a square wave, and no doubt it is an ugly one. No doubt it could have been made much better and much more efficient with the knowledge and the components we have today.

    But I only wanted to point out that I see no obvious design violation with this circuit (that would explain transistor failures), and nothing that sets it apart from other similar designs from this era - including ones suggested by the transistor manufacturers.

    But this is Andrew’s thread and it is about rebuilding the AEC 101. So let us allow him to continue to document his work, and let us save the theoretical discussions about inverter technology (old and new) for another time and place.


    Andrew, sorry, I didn’t intend to step on your thread too much. I will be very interested to hear how your rebuild works out. It is an interesting thread for me - and many others, I am sure.

    Lars
     
  6. Fred Winterburn

    Fred Winterburn Karting

    Jan 27, 2015
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    Lars, Yes we are getting off topic! My point however was that the technology existed long before the Dinoplex was made to produce lighter, more efficient power supplies and in fact this was being done by more than one manufacturer of CD ignitions, mosty in the USA. Fred


     
  7. dgt

    dgt Formula 3
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    Update: This stock system ran perfectly in the past few years after the rebuild and has done about 5k miles including 3.5k mile all over Europe last summer, to the Dino 50th in Italy through the Alps ( up to 2700m), in 35C heat etc.

    One issue as noted in other threads, the contact points available today are complete JUNK. I've been through 3 sets and they barely last more than 1k miles before the plastic material that contacts the lobes grinds down and closes the contact gap. Fortunately, it's pretty easy to tell when this is starting to occur and fix.
    I was able to find a NOS Marelli set but even they broke at the contact point with the distributor cam.
    There are no good point sets anywhere (Manfred and Matthias have told me this too) and I've complained to Superformance about it.

    Adrian notes that the Pertronix II is a good system to trigger the Dinoplex on dinoplex.org.
    I'm looking into replacing just the points with the Pertronix trigger inside the distributor to run the original Dinoplex. It all looks fully reversible.
    From various threads, I see folks have used the Pertronix system (trigger, coil etc.) but has anyone run a Dinoplex AEC101 with just the trigger?
     
  8. Fred Winterburn

    Fred Winterburn Karting

    Jan 27, 2015
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    Should be easy enough to trigger it from the Pertronix 2. Do not connect any pertronix wires to the coil. Instead, connect the red pertronix wire to the same +12V feed to the CDI, and the black pertronix wire to the CDI wire that would normally connect to the points. Fred
     
  9. dgt

    dgt Formula 3
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    Thanks Fred, yes I was planning on hooking it up as you said.
    In “Emergecia” mode which bypasses the Dinoplex via a switch, the Pertronix trigger would directly run the coil with a ballast resistor.
    Is that a problem?
     
  10. DinoLasse

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    Andrew, I am not trying to jump ahead of Fred here, but the answer is clearly: Yes, that would be a problem. You can not use the backup switch if you use any kind of electronic points triggering.

    Any electronic trigger sensor would not be able to drive the coil directly. At best, you would not get any spark at all. At worst, you would instantly damage the sensor. It all depends on how it is internally protected and current limited. You would need to have an additional power transistor (similar to the early transistor ignitions) to do the switching in backup mode.

    That is one reason why I insist on staying with mechanical breaker points. I like the system with a simple points triggered backup system. If there is a problem with currently available breaker points, it surely must be only temporary. High quality mechanical points distributors are being manufactured today for other marques, so it must be only a matter of time until the right manufacturer for our points are found. I understand why some may want to switch to electronic triggering, but I would never do it myself. A matter of personal preferences, I suppose. In my case it is also the desire to keep vintage equipment vintage, in addition to the ease of roadside repairs, etc.

    In any case, it is nice to hear that your rebuild of the AEC 101 was successful. If it survived that long hot drive during your trip in Europe, it will probably survive anything.
     
  11. dgt

    dgt Formula 3
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    #36 dgt, Mar 5, 2019
    Last edited: Mar 5, 2019
    Hi Lars,
    I'm with you, my approach to restoring this car was to make everything to the original spec and in working order as best I could, trying to solve the various known Dino issues along the way. e.g. I use the original starter and found a shop who knew about and could solve all the common starter problems without putting in a gear reduction unit, I've never had an issue with starting.
    I wanted a new Dino like the day it rolled off the showroom floor... so I tried really hard to keep the ignition system stock despite advice from others to put in a complete replacement system, some encouragement from Adrian that this is fundamentally a good system led me down this path.

    There were some adventures along the way like last July when the points failed on a pass in the Swiss Alps on the way to the Sils im Engadin, a 1 hour roadside swap and we were underway. If you're going to break down, do it somewhere with a view!
    The contact points are the one replacement part which have been so frustrating, I looked into remaking the small plastic wear part in the correct material and re-building them myself, or finding a substitute set from another vehicle until I became aware of the Pertronix 9MR-161A Igniter II setup for Marelli distributors.
    https://pertronix.com/electronic-ignition-conversions-test?year=1970&make=Ferrari&model=Dino 246GT&cylinder=6#auto

    It has an integrated reluctance sensor, power FET and micro-controller in a surface mount package and is completely inside the distributor
    It's a direct replacement for points on older cars, you keep all the original advance mechanism and they claim it will directly drive any coil.
    There are some other nice features like adaptive dwell with RPM, over-current protection etc. These aren't particularly useful with a Dinoplex but I believe it should be fine to drive the coil in "Emergencia" mode.
    Installation appears to be reversible, the magnetic rotor press fits by hand over the 3 lobe distributor cam and the baseplate screws into our Marelli S125 distributors. The only issue is the felt holder next to the cam which Pertronix note has to be removed but I'm sure that can be screwed back on with a little work.

    If some good points sets were available I'd just do that however this appears to be the best alternative for now. I ordered one and will probably build it up in a spare distributor to try, we'll see how it goes. It's almost spring here in New England...
    Best Andrew
     

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  12. pshoejberg

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    Andrew, I admire your patience and entrepreneurship in order to keep the old technology running on new points. I am awaiting your development of good quality points and in the meantime I enjoy my trouble free conversion to a red ugly MSD box:D Never looked back.....
     
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  13. DinoLasse

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    Andrew, I did not about these new Pertronics systems where also the power transistor is built in and hidden inside the distributor. Yes, that should work in backup mode.

    Regarding the starter motors, I think you were wise to stay with the original one. My car had been provided with the modern gear reduction starter before I came into the picture. I did not like it but decided to keep it anyway. Well, it just broke down, despite only very few hours of use! So, newer is not always more reliable.

    Nice photos, by the way. Your Dino picked a really beautiful spot to break down!

    Best
    Lars
     
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  14. dgt

    dgt Formula 3
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    The Pertronix trigger setup was installed in the Marelli distributor housing and I've driven 300 or so miles on it.
    As described earlier, I'm using this simply as a trigger for the original Dinoplex to replace the ever-failing contact points whilst keeping the original centrifugal advance weights.

    The installation was very simple, it can be done in an hour with the distributor out of the car and it's held in with a screw.
    The magnetic trigger that is a press fit over the cam was not very tight so I put a few turns of teflon tape to pack it.
    The only other issue was the instructions said to align the X stamp on the pickup baseplate with the hole for the wire connection in the side of the housing. There were 2 possibilities as it didn't line up very well with the screw hole so I chose one and it worked fine, or maybe it didn't matter...
    No adjustments are required, the gap to the magnetic trigger is setup from the factory.
    Externally, I had to run one extra wire back to the coil +12v and apart from this the system appears completely stock and is reversible.

    The car runs smoother and more consistently, particularly in the upper rev range. I'm very happy with this and fixed a very frustrating problem with little effort and $179.


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  15. DinoLasse

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    What a neat, clean solution!

    My previous objection to electronic triggering was that it appeared to prevent the use of the back-up ”emergenza” system. But since the Ignitor II module is designed to drive a coil directly, that objection goes out the door, I assume.

    Using the Ignitor simply as trigger should only be beneficial, I believe. The clean, stable and bounce-free trigger pulses are probably making the Dinoplex a bit less nervous than usual. Perhaps that is what you are feeling in your engine. Nice to hear!

    I may not be in a rush to replace my old mechanical points yet, but it is nice to know that this alternative exists. With the experience you have had with your breaker points, I can certainly understand why you want to get rid of them. Nice work, Andrew.
     
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  16. dgt

    dgt Formula 3
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    Thanks Lars, I didn’t try the emergencia mode but it should work.
    The timing light showed the timing to be more stable than before, it was always somewhat erratic with points.
    It’s not perfect as I’d have to remove the advance weights mechanism next, but still a big improvement.
    I like the fact there is dwell compensation with rpm, I suspect this and a clean trigger helps alot at high rpm over the available points.
    Cheers Andrew
     
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