Odometer failed

[l10tus]

My early car has a single odometer ( no trip) that has cleared itself of the overall recorded mileage, it clears every time I switch the ignition off, but starts working each time the car is restarted.

Just wondered Is this a self repair job - if so how?
Thanks,
Phil.

[sixor8]

I believe the early ones have an internal battery which fail. Not sure if you can do it yourself, but I'm sure somebody will be along with the solution.