65 Formula S tach rebuild service

This method works for the early console tachs that have an external sender...don't know if it works with dash tachs...

Test the tach with a "D" size battery...take yellow wire and touch "+" side of D-cell battery, take black wire and connect to "-" side of D-cell battery, needle should move to around 2,000 RPM and hold steady...if it does not move, it's dead

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