Request from my next door neighbour to have a look at a Sharp copier from his works. No model details at this time. Apparently it is basically non functioning, and produces an error code of "H4". He says that there is no reference to this code in the user book, so he doesn't think it is a user issue such as drum assembly needs replacing or paper jam or whatever. I don't see much point in wasting time on it unless we can find out what this code means so, accepting that I don't have a model number at this time, is anyone familiar with Sharp error codes, and know what this one means, assuming that they are generic across the range ?