konica minolta biz-hub c6500 2451-2454 errors

hi all
i have a c6500 and i keep getting error c2451 up to c 2454 error codes as well as c2411 and 2401 i have replaced the
developer
tcr sensors
check the developer drive motor
and checked the print board
is there anyone who can help me to get past these error codes so i may get printing again..

 

i tested the fuses on the print board to see if any had shorted
i also ran all the adjustments but as soon as i do the toner initialization the machine goes into the 2451-2454 codes before it completes it process