bizhub c5500 mfp errors

hi do you know of anyone that can help
i just got a konica bizhub c5500 mfp printer
it keeps showing error codes all indicating to the development section and sensors...
i checked the printer control board and have replaced the developer(tcr) sensors and i have also done the developer initializations mentioned in the the technical manual but i still keep getting the same error codes..
is there anything else i could do to get the machine to print

 

What are the specific error codes?

 

the codes change from 2421 till 2454 the... mostly 2454 is the most common...i have checked the dev motors and the print board replaced the dev sensors now i'm looking at the corona wires....