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11-07-2014, 01:42 PM
Hi Folks

I have a C451 that is printing horizontal yellow streaks (please see attached image). I have replaced the Yellow IU, transfer belt and printhead assembly with no results. There are also very faint horizontal cyan and magenta lines in the same pattern. Any help at all would be appreciated.


11-07-2014, 02:40 PM
If they were vertical lines I would suggest the drive motor or drive assembly - if you had another machine close by you could try swap them around but if they are horizontal I would have gone with an imaging unit. Sorry that's not very helpful but looks like charge lines to me but if that's been replaced I genuinely don't have a scoobies. It could possibly be power supply to the charge spiking but I wouldn't really know without seeing it first hand

11-07-2014, 04:43 PM
Got to the bottom of it after a long day swapping parts and boards between two machines. The problem ended up being the main board, PWB-MFP A00J-H020 (see attached image). I now have a licence management error message, would anyone know how to reset this?

Thanks for your help.27057

11-12-2014, 01:38 PM
Before changing the MFP try to clean contacts of RAM memory or swap just the RAM modules. 90% of issues with this machines behaving weird are related to RAM.

11-12-2014, 02:15 PM
Have you swapped the NV RAM?

Sent from my iDon't believe in marketing device using Tapatalk

11-12-2014, 02:40 PM
License management error is common after MFP board replacement. Verify you have the correct serial number entered in service mode, and if correct, you will have to call KM support (LMS Group) to have a repair code issued for your MFP. There is no charge for this if you are a KM tech, or have access to KM support. If you are not KM then you will have to have a KM tech come out for you, but the message does not affect any of the MFPs operations and can be ignored if you wish (assuming there was never an LKs added in the 1st place). Emujo

11-18-2014, 07:07 AM
Everyone has given sound advise.
Aside from a possible bad connection, I would add that before you replace the board try spraying it down with contact cleaner or using a toothbrush with 91% (or higher) isopropyl alcohol (dip the brush in the alcohol first!).
Also physically inspect it for potential resoldering repairs--especially capacitor replacement. Even better, test the capacitors with a meter capable of test capacitors already installed such as the Blue ESR.

11-18-2014, 10:29 AM
Thanks for all the replies folks. I had also tried swapping the Nv RAM chips before changing the board and the problem was still there. I had a spare board available so didn't look any further after the problem was fixed. 1 week gone and the machine is still printing streak free.

Thanks again

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