I wonder if anybody reading this has any experience of repairing / rebuilding electronic (CDI) ignition units?
The story so far.....
I picked up a cheap MacMinarelli (AvioMac) 70 cc twin. It has electronic ignition, not the more common magneto shown on their website.
The unit is labeled MacMinarelli but is so badly built inside I wonder if it is perhaps a prototype rather than a production model. Anyway, only one half produces a spark (proved by swapping the leads around so that the other cylinder ran. The engine starts and runs surprisingly well on one cylinder which is, I suppose, good news.
Opening up the black box showed clear burning above and around a "home wound" looking coil at the lower voltage end of one circuit. The circuit was crudely bedded in silicon which appeared to have been squirted in not quite filling the box or all the gaps - which probably caused the problem.
A replacement unit is (in theory) available from Italy for 250 euros which is far more than I'm willing to pay for an unproven engine.
I've picked out the sealent to reveal about the worst lash up I've ever seen on a type of vero board!
I've done a bit of electronics in the past so I suspect with enough care I could trace out the circuit. There are a couple of power transistors or thyristors on each side, a handfull of resistors, diodes etc. The HT coils seem to be integral with the HT leads, each linked to a capacitor.
Any comments / suggestions would be most welcome or if anybody could point me towards some circuit diagrams for these type of units?
Thanks
Chris
