Autometer tach adjustment

[Martin_80]

Hello,

I live in sweden, shipping is to costly to ship it for calibration at autometer, and they won't tell me how to do it.

My tach reads 100-200 more then the rev limiter allows, it use to be accurate. I have a Optimax 225 from 1999, non smartcraft! Can someone please tell me how you calibrate the tach, is there a pot? Is this something you can do by your self if you have a signal generator? What type of signal is it?