Smiths Tacho wiring problem

[Chris Todhunter]

Hi,

I've just bought a Smiths tacho for my mini, but now I've received it,
I've got no idea of how to wire it in.

On the front it has a model number RVI 1003/00. On the rear it has the
following connections:

-6v
+
012v
Bulb power connector
Another connector I can't identify!

Does anyone have any experience of these tachos or any ideas of how to
wire them up?

Cheers!

[Alex]

Post by Chris Todhunter
Hi,
I've just bought a Smiths tacho for my mini, but now I've received it,
I've got no idea of how to wire it in.
On the front it has a model number RVI 1003/00. On the rear it has the
-6v
+
012v
Bulb power connector
Another connector I can't identify!
Does anyone have any experience of these tachos or any ideas of how to
wire them up?

Erm, your indication isn't clear above. Does it have two +ve terminals
or what? If it has -6v marked and +12v then the 6v is for 6v +ve earth
cars, while the +12v is for -ve earth 12v cars.

I can't comment specifically on the above model, but usually a
revcounter (not a tacho, this records speed over distance, and I can't
see why you'd fit one) has four connections. +ve supply (be it 12v or
6v), earth (sometimes the case is earth, there is no separate earth) a
bulb connector (often a red wire) and another wire, which can have
various markings, or colours. It is often marked "coil" or C. This
"extra" wire is to be connected to the points/breaker side of the
coil, ie on the same connector as the lead from the coil to the dizzy.

Alex

[Andrew Mawson]

Post by Alex

Post by Chris Todhunter
Hi,
I've just bought a Smiths tacho for my mini, but now I've received it,
I've got no idea of how to wire it in.
On the front it has a model number RVI 1003/00. On the rear it has the
-6v
+
012v
Bulb power connector
Another connector I can't identify!
Does anyone have any experience of these tachos or any ideas of how to
wire them up?

Erm, your indication isn't clear above. Does it have two +ve terminals
or what? If it has -6v marked and +12v then the 6v is for 6v +ve earth
cars, while the +12v is for -ve earth 12v cars.
I can't comment specifically on the above model, but usually a
revcounter (not a tacho, this records speed over distance, and I can't
see why you'd fit one) has four connections. +ve supply (be it 12v or
6v), earth (sometimes the case is earth, there is no separate earth) a
bulb connector (often a red wire) and another wire, which can have
various markings, or colours. It is often marked "coil" or C. This
"extra" wire is to be connected to the points/breaker side of the
coil, ie on the same connector as the lead from the coil to the dizzy.
Alex

Some of them have a plastic 'loop receiver' sticking out that you wind a
loop of wire through that is in series with the points and coil. This
inductively couples the primary loop of the ignition coil circuit into the
rev counter. The 'loop receiver' is a square plastic lump that is retained
by a small knurled nut and pillar and also holds a metal hoop - this hoop is
vital as it forms part of the magnetic circuit.

Andrew Mawson