Early Smiths Tacho Wiring

[newman]

Hi all,

Have just picked up an early Smiths tacho from the father of a mate, it's been sitting in a cupboard in his shed for 30 years.He said it was working when he took it out of a car he had brought and thought it made the car look like a "hoons" car (his words not mine). Anyway it has a white cable looped through a plastic block on the back and a connection block of 3 terminals, 2 have cut off wires and the 3rd has a red plastic cover over it.The other wire is a light wire for the gauge, I don't want to wire it wrongly and damage the tacho and all the other tachos that I've fitted to cars before haven't had a "loop of wire" on the back. If any one can help I'd appreciate a basic wiring diagram as I think it will look period correct in my car as I'm staying with "Grey Power".

Newman