MP4500/Coil Back-up

[Caveman]

MP4500 - cleaning coil assembly packs with toner causing streaking on copies - replaced metal coil and cleaning mylar/paddle assembly - close inspection shows no blockage where used toner is transported from the coil to the front area of PCU - copies are not overtoned - all drive to the coil assembly checks with no problems - unit has 900k copies - problem started recently / no problems with coil assembly up until the last month or so.

All suggestions appreciated.

[E Winter]

still the first PCU at 900k? I'd go for a new one then - these aren't made for swapping just the PM parts for good.

[zed255]

I only PM the PCU assembly a few times and then just replace the whole thing. I find the plastic becomes brittle. Might be worth fitting a new one. Even though the copies don't appear over toned look for anything that may draw excessive toner to the drum, like quenching lamp dirty or not coming on.