xerox 252 not printing cyan anymore

Hi everyone,
I just changed the MOB sensor on my xerox 252 due to a faulty misregistration problem, and now the machine does not print cyan anymore.
Is this related to the MOB sensor? Registration is perfect now, but I still get all NEG on registration procedures. How is that possible?
Any idea about the problem with the missing cyan.
By the way, I changed IBT belt and put new cyan drum, still same problem.
your Help is very much Appreciated.

 

Could be several things.. The laser could be faulty but its probably the Charge HVPS (PN:105K20751/105K17680) Located on the back side of the door on the back behind the MCU PWB.

 

Is there a way to check the HVPS charge?
One important thing to mention: before the machine stopped printing cyan, it was spilling full solids of cyan over Ibt belt, every time we tried to print anything.

 

Update: the tech was here today, checked all the gears and Mechanics and changed Cyan developer. Now he is sure it's a voltage problem.
Because the machine starts to show the cyan, but prints a rough surface blue on whole sheet.
According to him, he never encountered this problem, and does not know how to fix it.
Any ideas? do you have a picture of the Charge HVPS (PN:105K20751/105K17680) mentioned above.

 

Dev tank is knackered. Get your tech to replace it. These machines go through tanks before the developer is due for change.

 

We Already replaced cyan developer tanks twice. When we put a new tank it prints a solid cyan rough surface over the sheet, then the cyan developer gets empty and it starts to print without cyan

 

The tank empties?

 

No the tank is not empty. What happens is when we put new Cyan Dev. Housing, it prints a rough blue surface that covers the sheet, after few prints, the cyan disapears and it prints only K,M,Y

 

If you could post a pic it would be nice. I work on 5-6 Docucolors a day, 80% of the time its the Charge HVPS. It charges the Drum to receive the toner.