I have the above printer which I am working on. First the fuser unit was bad and I orderded a new fuser unit .After replacing it the printer began to display error 50.11. I could not find the explanation to this error code in the serfvice manual that I have. However I decided to replace the element. After I did that the machine changed from error50.11 to "wrong fuser intstalled" What can I do to fix the problem?