hiya,

just as a suggestion as i had speedo needle play silly with me before and it came down the physical worm gear in the rear of the dash, so after opening the back of the dash up and prodding it was fine. If the needle doesnt move atall (10k or behind the stop it sounds like a physical thing as opposed to the electrics side of thing. But not sure if it may be that simple as the rev' works as a volt meter it may be getting to much power from an unknown source.

Not sure if this is any help, but best of luck.