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Attachment 2, Autopsies

-610759 and 610906

Figure B-1

Over ten years ago, I started soaking failed ignitions in acetone to remove the epoxy and to see what was inside. It usually took three units to come up with the circuit diagram. I was able to make measurements on discrete components and locate test points. This helped me learn how these things worked, what was broke, and how failed components might be replace.

Autopsy 610759 / ESKA Single

Figure B-2

Figure B-3

In Figure B2, Pcfoil4.jpg, I do not see diodes D1 and D2 so it must be a configuration B.

Figure B-4

One of the last things I learned was that "C2" is a thermistor not a capacitor.

Figure B-5

In Figure B4, NackedPT.jpg there are a couple interesting things to note here. The Pulse Transformer core is made of Ferrite like that used in radios and tv’’s at radio frequencies. Magneto ignition coils have iron laminations for the core which does not respond fast enough the DCI application. The core material in Magneto coils takes time for the magnetic field to develop and decay. Thus one cannot substitute a magneto ignition coil for the Pulse Transformer. Also, in the magneto ignition coils, the spark is created when the primary current is interrupted. Here it spark is created when the capacitor voltage is applied to the primary. Thus a CDI is not a magneto.

Autopsy 610906

Figure B-6, abvssi2.jpg

Figure B-9

Figure B7

Figure B-8

If someone is good in electronics, they may try to repair a failed unit. If I ran a unit on the simulator and it fails to put out a spark at very low RPM, but does at a higher RPM, I would suspect a leaky main capacitor. The 610855 and 610748 are similar and also might be repairable.

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