Im working on converting my tach using the Spiyda rvi to rvc electronics. I need help determing the wiring to be done. I understand the 2 small wires go to the + and - on the tach, but not sure where to solder the larger red wire and Which pad on the board to solder the last (4th) wire. My tach had 2 black and 1 green wires going to it. Ive observed 12v to the Green wire and one of the blacks when the key is turned on.
Thanks for the wiring help.

 

Anybody do this conversion?

 

Anyone do this conversion?

 

I can kinda understand bumping a thread when it falls quickly off the front page of a busy forum, but what do you think you're accomplishing by bumping a thread that's already in the top 3 posts on the first page?

Other than annoying people, I mean.

 

Looks like no one is familiar with your electronics, me included, but maybe I have some clues. Your original tach was triggered by current pulses going to the coil. One of the 2 black wires connects to 12v then enters the tach, loops through an inductive pickup (the large white thing) then exits and goes on to the coil plus terminal. The green wire is from a different 12v source and powers the tach circuitry. The last connection is ground through the mounting hardware. Your new tach operates differently and is most likely triggered by voiltage spikes present at the coil minus terminal. You will need to provide that wire.

1. Remove the black wires from the tach and solder their ends together. Now you have power going to the coil. At this point you should check that the engine runs.
2. I assume the red wire on your new pcb is for power and should connect to the green wire, Ground is probably still through the tach mounts.
3. You now need to connect the coil minus terminal to the correct terminal on the pcb. The electronics must have come with directions that identify that point and hopefully agree with my comments above. There should also be a method to adjust the tach reading.

This might go smoothly but may be a lot worse. I am quite familiar with the subject but that does not guarantee that I am correct. Many assumptions based on your photos. So if there is smoke, I am sorry but I warned you. You might also consider hiring a pro if you have doubts or sending.the tach to a place like Nessinger for a rebuild. You did not mention why you are doing this change but everything above is reversible if need be. Good luck.