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Delta Mark Ten B Capacitive Discharge Ignition CDI box

It appears to have been made in 1973, per the date codes on the transistors, and the dated instructions.

The Mark Ten B is a capacitive discharge ignition. What it does is store up electrical energy in a capacitor, then when triggered it sends this energy to the ignition coil. The voltage sent to the coil is higher than 12 volts, so the coil puts out a hotter spark than it would with just ignition points. CDI is not quite the same thing as Multiple Spark Discharge (such as the Autronics MSD box), which sends a few high voltage pulses to the coil with each time the plug is supposed to fire (at low speeds).

this is the decal that came with the "new in box" Mark Ten B that I have.

This is a used late 1968 Mark Ten. It also came with it's box.

I also have a 1968 Deltakit Mark Ten assembly manual, see the schematic here.