Ryan
You will get 12 volt at the three pins with the ignition on as two are the impulse loop from the ignition where current flow is read when the engine is running and the third is the 12volt supply.
I agree check the flexible pcb to see that the earth connection is not broken to the tachometer. This is the fourth and final connection and often a problem.
The next question is; Are you using a points or electronic ignition system?
These tachometers do not work correctly or at all on electronic ignition.They can be converted if necessary.
Beyond that its down to the circuit. I am sure there are details on the net about repairing them. Yes capacitors and other components are a problem, connections and solder joints, the meter movement and cleaning etc. it's not brain surgery given that I can do it most of the time. Like anything practice makes perfect and even now we learn something new every day even about this 'simple' smiths circuit.I watched my father struggle with one the other day and he has been repairing them for 42 years this month.
Unfortunately your available repair options are now down to one in Perth, the other closed recently due in part to our 'do it yourself nature'.
I appreciate the referral above, you can post it over if you get stuck or if you visit I have my 850, van and Marcos at work at the moment that I can show you. Sorry I don't have any clubman's.
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