unknown

asked Mar 9, 2014 at 8:48am
Hp HP Color LaserJet 2840

HP Colorlaserjet 2840 does'nt recognize cartridges

During boot up the control panel states "Install cartridges" with a "?" over each designated color on the panel. The cartridges are installed correctly, they are all HP genuine cartridges, and the carousel is perfectly aligned. The machine does recognize the installed drum, just not the 4 cartridges. I have checked all of the contacts on each cartridge and have cleaned the contacts on the toner sensor PCA board as well. There are not any error messages displayed on the screen, just "Install Cartridges." Has anyone come across this problem before? Any help would be greatly appreciated. I have taken the machine apart no less than 10 times looking for a problem.