Any Heathkit experts out there? Tachometer help needed.

Factual Questions
1

I’ve got a Heathkit Tachometer in my 1970 VW Bug, and I like to return it to working condition. Yes the one with the digital readout and the cheesy wood trim. Model CI-1079 if I’m not mistaken.

There are 4 wires, a red and black that I assume are power and ground (hooked to the fuse panel and ground), and two more smaller gauge wires, red and bare (not currently hooked up).

How is the tach triggered? Am I missing a pickup? Does the red wire hook to the points?

Should I just suck it up and drop $30 on a modern tach?

2

Go here. Heathkit Schematic and Manual Archive | Vintage Radio Info

Then do find on page search for tachometer. Download schematic.

3

The tach’s signal input is typically connected to the negative (primary) terminal of the coil, which is connected to the points. The coil terminal is usually the most convenient place to access that portion of the circuit. It’s probably a good idea to make sure the coil isn’t wired backwards (it happens); + to 12v/ign, - to the distributor (points).