Electro-tach

[enjenjo]

I have an old tach here, brand name is Electro-tach. I believe there is some connection to Dixco.  Anyway, does any one have any idea how it's wired? There are three wires out of it, one by itself, and the other two made together like speaker wire. All of them are about 18 to 20 ga. the single wire is black, the other two are grey.

[Charlie Chops 1940]

I believe black is ground, one grey to+ign,  the other to signal (coil).

Charlie