Stack Dials are telling me lies!!!

Hi,

Can anybody help with a rather annoying problem that keeps happening with my Stack dials?

They keep �hanging� indicating incorrect revs and speeds. Then on other occasions, they are moving but totally out of calibration!

The rev counter and speedometer are affected independently of one another. Usually go tits up together, but not always.

I have tried pulling the 7.5 amp fuse out to cut the power, this seemed to work once but I think that was a coincidence as on the odd occasion they have recalibrated them selves.

Any help is most appreciated.