Can rallye dash tach work with electronic ignition?

I have a '70 Duster 340 with rallye dash but tach is not working.
I think the car was converted to electronic ignition at some point, and wonder if that is the reason the tach won't function? Previous owner installed tach under dash in front of shift lever.
He must have done that for a reason.

Tachs usually run off the coil, so ignition type doesn't usually matter.
It was probably just easier and cheaper to put another one in than fix the OE.