I have a HP signal generator (yeah I'm a nerd) that I use to test tachs and other electronic junk. It duplicates the pulse train you'd get from a distributor trigger. Other than that, I don't know how you could test one. The signal generator route is an expensive proposition.
1970 SS 396-350hp
Frame-off Resto: Just Say No! 4 years and counting...
The signal generator is the best way, but if not- Got a distributor and coil hanging around? You will need a 12V battery, distributor, coil, plug wire, plug, drill and a few wires. You spin the distributor with the drill.
Hook up +12V to + side of coil and +12 terminal on tach. Ground wires from Neg battery terminal to distributor housing, spark plug base and - or gnd term on tach.
Spark plug wire or coil wire from coil to spark plug. Negative side of coil goes to tach teminal and points. Spin the dirstributor with the drill. Will only go up to 1k or so but at least you will know if it works at all or not.
Steve Strasemeier (70SS 396, Fathom Blue/White Stripes) My 70SS
A forum community dedicated to Chevrolet Chevelle owners and enthusiasts. Come join the discussion about restorations, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more!