[Mgs] Coil for 1980 MGB (was intermittent miss)

[Peter Schauss]

Thanks to those of you who responded to my previous post about the
intermittent miss.  I discovered that I had a new coil on the shelf which I
apparently had bought several years ago so I decided to replace the old one.
The coil I used was Moss part # 143-230 which is the one listed for years
75-80.  The label on the coil says that it is to be used with a ballast
resistor (1.5 to 1.8 ohms iirc) and the wiring diagram for my car says that
it has one.  There are two wires feeding the positive terminal of the coil.
With the ignition on, one wire showed zero volts while the other showed
about 12.5.  The 12.5 volt wire comes from the CEI amplifier and I assume
that the zero volt wire comes from the starter solenoid.

If the system is ballasted, shouldn't the wire coming from the CEI amplifier
show 6 volts or is there something different about the CEI ignition system?

Thanks,
Peter Schauss
1980 MGB