Yellow background on printouts

[Alchron413]

I am having an issue with my go m551n printing out yellow backgrounds on color prints but not so much on regular prints or even internal test prints.  I have changed out the yellow toner and also changed the ITB belt and secondary transfer roller, as well as installed a DC controller board and lifter assembly earlier for a separate issue.  Would firmware or drivers be an issue since the customer is using UPD drivers instead of PCL6 drivers? Pretty stumped on this and looking for thoughts on it.

[Repairatrooper]

Not a driver issue. Are these Oem or 3rd party toners.?Maybe you have two bad yellow cartridges. 

[Alchron413]

Yes, they are OEM toner cartridges they are OEM cartridges

[Ccarbajal]

Have you tried cleaning the contacts for the yellow toner unit on the machine? If it's not making clear contact it could effect the charge  coming from the HVPS to the drum. I.e dirty, bent, or missing pins. If you still have the problem it could be bad luck with two bad toners in a row, alternatively it could be the HVPS. Updating the firmware is always a useful troubleshooting step. If you're there and its not up to date you could eliminate that from being a possibility while you look around for other probable causes.

[Alchron413]

Right now I'm waiting to see about getting some new official cartridges and yes I did clean the contacts inside the machine where the drum connects to the back.  Only other thing I think it could be is something with the hvps connections, so I'll update once more progress has been made.

[Alchron413 · Accepted solution]

Ok after doing some testing I have finally figured out what the issue is, it comes down to the springs that are on the backside of the HVPS board.  After finding out that the customer has been using canned air numerous times inside the printer, they had actually coated the HVPS with enough dust and toner that it made the bridge connection on the board blocked off.  After cleaning it and vacuuming out the rest of the residue the printer is working great with no yellow pages and full color on every print job I sent to it.  Just as an FYI if you get this issue check your springs on the HVPS because that could be your issue if it isn't the cartridges being defective.