That is how it started,
The rev counter died when the alternator did, the rev counter was replaced a
few months ago but i haven't looked into it until recently.
I have confirmed that the fault lies in the rev counter itself, since 2 IC's
inside have been found at fault
I'm assuming a large surge of unregulated AC or DC made its way to the
input of the rev counter and kissed them goodbye.
With an oscilloscope you can see a nice cleanish sine wave at the input of
the rev counter which changes in sympathy with the accelerator pedal.
I am finding difficult to source 1 of the IC's so I need the rev counter.
Cheers