Can you calibrate a repro tach like that sold by TPP or OPGI by simply putting a potentiometer accross the picups on the tach as in the following link?

http://www.mindspring.com/~jayk3/toyota/tachmod.htm

Another question:
To test your tach if it is out of the car and you do not have a signal generator could you use a laptop and a software tone generator like:
http://www.world-voices.com/software/nchtone.html ?

I am not sure if the output from the audio jack has sufficient power to drive a tach .

Sorry for the double question.
Thanks, Peter

 

The signal needs to be 12V (although modern electronics might trigger at 5v), so the audio output probably won't be enough. But feel free to try! It shouldn't break it.

I'm surprised a repop needs recal. It should have modern internals that are pretty good.

 

Thanks. I bought it at The Parts Place so I want to make sure it works before I go through the exercise of installing it.