Smiths Tachometer RVI to RVC conversion board -566-

In stock

A replacement circuit board to convert a Smiths RVI tachometer to RVC.

download installation instructions RVI-RVC.pdf (Large File)

The board is negative earth and will convert positive earth tachometers to negative earth unless the optional positive earth kit is included.

Fits Smiths/Jaeger RVI

Many tachometers from the early 160s on not marked with the Smiths Logo

such as UK built Fords

Datsun ( built under licence in Japan)



Converts RVI tachometers to RVC. (2020 version)


All new electronics replaces old circuit board

High quality ceramic capacitors for long life and temperature stability.

If your classic car has had electronic ignition fitted and you tacho won't play ball, this will solve the problem

Based on the LM2917 but with spiyda's own additions

Uniquely, this unit can be calibrated from a PC, Laptop, iPhone etc. using the calibration cable (now even more sensitive)

No need to intall software, just a simple wav file.

If you are fitting the board yourself, order the optional calibration cable.

We can also fit this item for you, we will ultrasonically clean the movement, fit the board and calibrate it for you

applies to UK only except by prior arrangement, contact us for shipping address etc.

(we will not carry out any cosmetic work on the tacho except by prior arrangement)

Note:- you will not need a calibration cable is you take up this service.

*  Note:- there is a surcharge for fitting the board to tachos with a rolled-on bezel. In most cases a new bezel will be fitted.


This board only fits tachometers with the movement shown in the picture. It mounts on existing tapped holes and therefore will not fit other types.

The board is negative earth and will convert positive earth tachometers to negative earth 

The board will drive a clockwise tachometer clockwise but we can modify RVI tachometers to operate anti-clockwise



Videos of the Tachometer 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

One customer's (Ed)  videos of the Tachometer conversion on Tube
RVI to RVC Video 1
RVI to RVC Video 2


More information


Tachometer Wiring

Tachometer Calibration


Note, 1

there are now four inputs on the board.

They vary in sensitivity from the very sensitive calibration input, to the much less sensitive high voltage inputs.

to clarify how these are used depending on your set-up

for calibration with an audio signal the low voltage input should be used
if you have a tacho output the low voltage or TTL input should be used.
if you have standard points and coil, or electronic points and coil, one of the high voltage inputs should be used,
if the tachometer does not trigger correctly then it is OK to use the alternate high voltage input.



Note 2

unfortunately a customer recently sent us a tachometer through the post and it was badly damaged...

to protect the unit in transit, first cut out and tape a disc of something stiff (like hardboard or thick plastic) over the front

this will protect the glass ( I recently had a customer send one with an old CD taped over the glass.. ---  perfect  !! )

then wrap the whole thing in bubble wrap and put it in a box no bigger than 350mm x 250mm x 160mm  (UK SPECIFIC)

this is a special exception to the royal mail small parcel sizes..  it makes a big difference to cost..

Insurance is up to you...  personally the hassle of trying to get money out of the post office is more trouble than it is worth..

so I generally go for a signed for service.

If your tachometer is very valuable use a special delivery service, please let us know and we will do the same in return.
Remember to include at least a clue as to who the tacho is from !!   and an indication of how many cylinders for calibration purposes
Note 3

We have included more power supply cleaning up circuitry on this latest version of the board.

Note 4

We have altered the board a little to make it easier for those driving it from the "W" terminal of an alternator. The frequency of pulses is higher than ignition pulses, so there are a couple of places on the board to cut to enable the board to respond correctly, these are detailed in the instructions.



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