Tach not working on 914-6, Not my car unfortunately... Options

[Nogoodwithusernames]

I'm trying to be of some assistance to the guy in town who is getting his -6 put back together and troubleshooting the myriad of little issues after a restoration. We already figured out that his speedo drive got swapped with a 911 unit at some point so he has the correct one on the way.

The issue at hand is tachometer isn't working. All gauges were rebuilt. I can't remember who he said did them but I recognized the name as a reputable place.

The tach has the purple and black wire hooked up to it, but there does not seem to be a purple and black wire back at the coil. Just the main wire to the distributor, and one wire on each terminal.

Any ideas of what to look for and check? Are we missing something obvious?

[ClayPerrine]

The tach adapters were just small coils. And they are prone to dying.

I have three of them, and none of them work. I converted the innards of the tach on our 70 six to a later tach and took the tach adapter apart and put a jumper wire inside so it LOOKS good, but does nothing.