Suddenly my car ( 911 targa made 1976) engine stopped. I get no sparks at my sparkplugs. Checked cd box (3 pin )as below. Point B supplied with 12 volts (+). Point A measured with no volts (I suppose must sent 100 volts to coil with ignition key ON ) Point C is connected to DISTRIBUITER. Strange thing is that point A it seems is having contact with ground (-) all the time. Any idea ? Any idea for upgrading to more modern ignition like MW PRO-10 if my cd box is burned and how risky and kosty this will be ? Thanks for reading and possible answers !