123 Ignition & Rev counter

[richard582]

Daimler 420 engine with 1-2-3 Ignition system. #
Where does the output for the rev counter (impulse type) connect to?

Thanks for any leads, Richard

[richard582]

I'm told that an impulse type rev counter can be connected to the negative of the ignition coil.
If that stalls the engine then connect via a 6.8kOhm resistor to limit the load (?)

But another said that doing this risks damaging the output stage of the 123 Ignition System.

Is there any truth in this as I'd have thought feeding a 12V pulse to an ignition coil is a strong job anyway and not likely to be affected by the current taken by an additional load of a rev counter?

The pic is of the rev counter -- it was salvaged from a 420G I believe