Hi all

I just got my tach in the mail from AutoInstruments. They rebuilt the tach and replaced the circuit board. This is a Tic Toc Tach from a 68. I wanted to get it re installed this weekend and ran into a wiring question. They are closed so I can not get in contact with them.
Before the rebuild there were three wires on the tach.
One for the Clock 12 volts, One for the Coil connection and one for the 12 volts supply to the tach.
After the rebuild the 12 volt supply for the tach is not there. There is no wire to connect to the 12 volt post from the circuit board.
My question: With the new circuit board can the tach just operate off of the coil connection and the ground and not require a 12 volt constant source as before.

Thanks
Ray

all tach's require a 12 volt source. Normally that is supplied to one of the studs on the tach unit by the 68's cluster pcb.

If you look at my pic of a hacked up modified 68 standard pcb, the lower left stud on the tach is IGN power for the tach, lower right is BAT power for the clock, top is tach coil signal. These are the 3 insulated studs in a triangle around the clock.
http://home.comcast.net/~Jimragtop/tt1.jpg