Magenta printing faded on docucolor 250

[alex4alltimes]

Hello everyone! My Docucolor 250 machine doesn't let me have peace for a day. It is printing faded magenta on the whole sheet. The magenta prints like bands and the print has lost its sharpness too. Please help! I have ordered new developer housings for yellow and magenta and also new developer materials for all the colours. Will it solve my problem? Also please someone guide me regarding changing of developer housing and adding new developer and changing the nvm values around with pws. I will be much obliged really! Thanks!

[InterfaceP]

Can you post a pic of the image?

[alex4alltimes]

Can you post a pic of the image?

Hi InterfaceP! Here is the picture you asked for. I have changed the developer material, fitted a new developer assy and also changed drum unit. But no joy.

[InterfaceP]

I would start by checking the 1st BTR "Magenta" swap it out with another color. After that I would look at the Developer BIAS PWB.

[alex4alltimes]

I would start by checking the 1st BTR "Magenta" swap it out with another color. After that I would look at the Developer BIAS PWB.

Hi InterfaceP! As directed by you I have swapped the magenta 1st BTR with the cyan. But the problem remains. What should I look for the developer BIAS PWB? The connectors look OK to me. I should mention here that a couple of days back the black scorotron was giving error 91-320 even though the wire wasn't broken . At that time I happened to detach the AC driver and the LVPS from the machine and reattached them later on after cleaning them and putting the connectors back. The problem regarding the error code 91-320 was subsequently gone after I kept the black hvps on for a couple of minutes from the component control.During that time I had removed the black charging connector from the back and reconnected it again. However after assembling the machine back all of a sudden the magenta started fading (was uneven). I thought maybe the developer assy was bad and the developer was also quite old. So I changed both. I thought it could be some erratic connector in the AC driver and LVPS section which I had overlooked. So took them out for the second time and put them back together after checking whether any fuse was gone or wires were chipped or if any connector got left out. But it was all OK. Next I reconnected all the MCU connectors and the Dev BIAS and charging connectors. Still the same. Next changed the drum unit. Ditto. Please help. I think the BIAS PWB is OK. I have checked and its voltage is OK according to the SM. Out of my depth now.

[adriansto]

Print A3 page with 100% magenta from machine service menu.
Stop the machine while printing and check the image on magenta drum.
If it is fade then you have problem with ROS or with developer unit.
Check bias on developer roll, look how the magenta magnetic brush appear, check if the developer roll rotate.
Also you can check if the magenta drum aluminium part has good conection to machine ground.

[alex4alltimes]

Print A3 page with 100% magenta from machine service menu.
Stop the machine while printing and check the image on magenta drum.
If it is fade then you have problem with ROS or with developer unit.
Check bias on developer roll, look how the magenta magnetic brush appear, check if the developer roll rotate.
Also you can check if the magenta drum aluminium part has good conection to machine ground.

Thanks Adrian! Looking into it and will let you know soon.

[alex4alltimes]

Hi Adrian! The magenta drum unit was replaced by the cyan and yellow drum unit with no positive result so ground is ok. Next the developer is rotating because the developer motor is rotating cyan and yellow developer also. Both these colours are fine. I had opened the ROS but it was after the problem started. And the ROS was only cleaned in the mirrors and the 2 glasses under the assy. The Developer Assy is new. Also the Developer dust is new.

[adriansto]

Hi Adrian! The magenta drum unit was replaced by the cyan and yellow drum unit with no positive result so ground is ok.

??

[alex4alltimes]

??

You asked to check if aluminium part of the magenta drum was properly connected to the ground. I had put the cyan and yellow in place of magenta. All of the drums cannot be faulty. so I take it the ground is ok. Or I am missing something????