MP2851 with random black dots

[luca72]

I actually had a used 1027 drum with me that just had a thin line on it.
I swapped it in to test and it had the thin line plus all the dots.

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..and then friend the only solution and disassemble it, it's so easy and fast, and replace the components one at a time, and try, even the frames! separately, even the black plastic part that electrically connects the charge roller, once a colleague has unsoldered the ball that is inside and I don't remember exactly, but it was a strange defect

personally this defect has always seemed to me more an electrical disturbance than something to do with toner

[copyaction]

Well I feel dumb now. It was actually happening before the drum. The two foam rollers just passed the paper trays had completely deteriorated.

[luca72]

Well I feel dumb now. It was actually happening before the drum. The two foam rollers just passed the paper trays had completely deteriorated.

If I understand correctly, do you say that the powdered foam has joined the drum / charge roller? Looking at the pdf I don't see a repeat from diameter, it seems a little 280k print to have such a problem, but where is it installed on the beach?

[copyaction]

If I understand correctly, do you say that the powdered foam has joined the drum / charge roller? Looking at the pdf I don't see a repeat from diameter, it seems a little 280k print to have such a problem, but where is it installed on the beach?

No it was the two foam transport rollers in the paper path.
Toner was sticking to the deteriorated foam and being transferred to the paper prior to it reaching the drum

[luca72]

No it was the two foam transport rollers in the paper path.
Toner was sticking to the deteriorated foam and being transferred to the paper prior to it reaching the drum

Ahh, now I understand, interesting!
have you tried cleaning / replacing that roller and the problem is gone?
But was the machine very dirty in general?
Usually that problem is either the pcdu or the transfer roller.
I must point out that I am a cleaning maniac.
Since this lengthens the interventions a little, my boss often tells me on the phone: "ohh, but are you still alive? But what are you making love with machines?"