1200 mag with open coil primary?

[digidocs]

Hi VAF,

It seems I've come across a Bendix 1200 series magneto with an open primary coil. Has anyone seen this failure mode before?

It seems strange to me that the primary side of the coil would fail because the wire is much heavier and there are fewer turns, but I guess anything is possible.

I arrived at this conclusion when I hooked up a magneto timing box and it consistently indicated open circuit on that mag when the points were open. I confirmed with a ohmmeter from the p-lead terminal to ground---when the points are closed the resistance is almost zero, but when they open the resistance is infinite (there is no longer a path to ground through the primary side of the coil).

Thanks!