I am working on a Xerox 250 and installed the whole Depense Assy from another working 250. Why is the toners not being recognize for the black? The toners are OEM and I even installed brand new and it still won't see the new toners. It comes up with toner missing or reinstall. Do you have to transfer the small boards that reads the toner from the original machine or do you have to do a NVM. They both are xerox 250