I've read a lot of the posts concerning HP printers and the "incorrect\ncartridge" error. Many of them discuss software issues. I can assure\nyou, my problem is not a software issue.\n\nMy HP PSC 750xi is a standalone unit. It is not even connected to a\ncomputer. However, after installing a new black cartridge, I am\ngetting the "Incorrect black cartridge" error.\n\nI have tried everything to fix it except to buy another new cartridge\nwhich I plan to do tomorrow.\n\nThe black cartridge that was originally in there did not seem that\nold. It was printing fine and then suddenly said the black ink was\nlow. That was it. One page of light print and it was gone. I used\nthe cleaning utility and that did not help. I aligned the cartridges\nand that did not help. I bought a new black cartridge and that did\nnot help. I cleaned the new cartridge and contacts and that did not\nhelp.\n\nSo my error is definitely not software related. Any suggestions would\nbe helpful since HP's suggestions did not fix the problem. Thanks.