Wav files for Tachometer calibration
from the column for your engine type choose an RPM somewhere near the middle RPMs
download the Wav file from that line in the table (right click and "save link as")
connect power and ground to the Tachometer
connect the red calibration lead clip to the tachometer input
connect the black calibration lead clip to the tachometer case
connect the other end of the cable to your laptop, computer, iPhone etc.
No other cables should be connected .. eg no connection to the car ignition system
With the tachometer in the orientation it will be in the car
Play the wav file at full volume, (if using windows media player, select "loop" to play the file continuously)
the tachometer should respond
adjust the tachometer to show the appropriate RPM in the table
The latest instructions for installing our RVI to RVC board can be found here
An FAQ with further useful information can be found here
If the tachometer does not respond to playing the wav file then you can try the following
increase the volume on the device playing the file
try with various combinations of bass and treble (tone)
try switching the red and black calibration wire connectors.
the sensitivity of every board is tested using a standard signal, so don't give up,
if you cannot get the tachometer to move, try another device,
A last resort is to disable a circuit protecting component on the board to increase the input amplitude. Details found here
Keep an eye out for the few tachometers that have the red and black wires switched..
the board will try to make the needle move the wrong way..
If this happens, you will need to switch the thin red and black wires
Videos of the Internal Conversion on YouTube
RVI to RVC 1 dismantling the tacho
RVI to RVC 2 fitting the circuit board
RVI to RVC 3 powering up the board
RVI to RVC 4 calibrating
RVI to RVC 5 alternative connections
the external resistor mentioned in the videos is no longer required
Checking calibration with an acoustic tachometer
For calibration on the car, a simple (although not always successful) alternative to a rolling road is to use a smartphone acoustic tachometer app.
We have tried two android apps (We have no affiliation or connection with these products) with varying degrees of success !