70-74 tach problems

[rcmotorsports]

The tach on my 73 Cuda stopped working. Ordered and replaced board with new style that works with electronic ignition. Won't work. Hooked up straight to battery and -side of coil. Tested on wife's Dart, works fine, buddy's Cuda, works fine. 67 points style Mustang, works fine. Changed coil on my car, still no good. Any ideas?

 

[Chryco Psycho]

power feed is suppling 12v ? Signal wire connected to neg has continuity with a test meter ?

 

[rcmotorsports]

12v yes. How would I check continuity to or from coil? What points would show? A ballast resistor replacement has been suggested, picking up one of them today. Thanks for reply

 

[rcmotorsports]

I have solved the problem. Found that coil wires were reversed when replaced. Switched wires around and tach working well. FYI, a car will run if coil wires reversed.

 

[Chryco Psycho]

Glad you found it , I figured either the signal wire was broken or the wires were connected wrong at the coil