C450 with no color

[rindraintsoa]

Dear all,
I have a problem with my C450 machine, I know this is a quite old machine but it did work for a long time. 2 days ago, the machine doesn't print Yellow/magenta/cyan. When I send 4 color print to the machine, only the black portion of the image is printed. all over colors (CMY) are blank. When I see on the state confirmation on service mode, I can see that all the IU are rotating correctly (I can notice change in the TCR level inside each IU), so I think the drum and developper inside color IU si rotating correctly. But no printouts, only black portion of colour is printed. I inspected the retraction mechanism of the transfert blet but didn't found any abnormality, the TB seems to work good. Would you guys suggest me any action to do or to check because I am desperatly looking for a solution to my problem. I would like to mention that I have P6-P7-P8 warning message relative to CMY IU. Perhaps it would help, but anyway when I try to sawp with a new IU there is always the same problem.
Thank for your quick reply

[rindraintsoa]

Dear all,
I have a problem with my C450 machine, I know this is a quite old machine but it did work for a long time. 2 days ago, the machine doesn't print Yellow/magenta/cyan. When I send 4 color print to the machine, only the black portion of the image is printed. all over colors (CMY) are blank. When I see on the state confirmation on service mode, I can see that all the IU are rotating correctly (I can notice change in the TCR level inside each IU), so I think the drum and developper inside color IU si rotating correctly. But no printouts, only black portion of colour is printed. I inspected the retraction mechanism of the transfert blet but didn't found any abnormality, the TB seems to work good. Would you guys suggest me any action to do or to check because I am desperatly looking for a solution to my problem. I would like to mention that I have P6-P7-P8 warning message relative to CMY IU. Perhaps it would help, but anyway when I try to sawp with a new IU there is always the same problem.
Thank for your quick reply
Any suggestion?

[minimerlin]

Have you looked to see if any colour image is formed on the transfer belt? HV?

[copier tech]

If the IDC sensors are dirty this can cause the machine to only print mono, clean them if you haven't already.

[Copier Builders SA]

How about changing the transfer belt? Even if you put in a used one just to see if it fixes the problem?

[rindraintsoa]

Thanks for all,
I have tried to replace the Transfert belt but the the same symptom occurs, I mean only the black portion of colour is printed out the others are not. I have cleaned the IDC sensor but still the same issue, any other suggestion?

[minimerlin]

Thanks for all,
I have tried to replace the Transfert belt but the the same symptom occurs, I mean only the black portion of colour is printed out the others are not. I have cleaned the IDC sensor but still the same issue, any other suggestion?As I asked before..is any colour image produced on the transfer belt at all? If not maybe you have an HV problem. Are you sure the colour IUs are turning?

[Tonerjockey.com]

1. What happens if you do a single color copy? Is it blank? Is it allowed?
2. Are you certain no one has turned on color restrictions for public users?

If you simply aren't getting any color output and there are no restrictions turned on, then you are probably looking at the MFP board, the controller board, or NVRAM. There is an outside chance that it could be a memory problem, but I doubt it. It also might be worth flashing firmware with the current version.

[rindraintsoa]

Thanks for all suggestion,
I have swapped the transfert belt with another working one but still the same issue, I have also swapped the PRCB and the two HV (HV1 and HV2) but still the same problem.
Another suggestions are welcome.