Does anyone know how to check a tach out to see if it works before installing in the dash?

I'm having the same problem. Just bought an original tach for a 69 and installed it in the dash and it does nothing. Checked the wiring with a dwell meter and everything seems fine. I guess I'll have to remove it and hand wire it up. If anyone knows how to test one to make sure it's working please respond. Thanks

I checked mine (68) by running a lead from the negative side of the coil to the "tach" signal input to the the tach Battey + to the b+ part of the tach and grounding the base. Worked great. Hope this helps-Dan in WV