Samsung ML2250 distorts the image when printing...?

Question

Seal

Good day, I got a Samsung ML2250 printer for repair, all printing defects were eliminated, except for one wave =) I disassembled the polygonal mirror, cleaned it ... The printer disassembled, cleaned ... After assembly, the first print came out as it should be even, the second one , the third one is the same ... only distortions in other places ... I sin on polygonal. Has anyone had similar problems, what could be the problem?

Answer 1

After re-dismantling and more thorough cleaning of the LSU and that mirror on the side (which I seem to have missed last time) the problem is gone.
Printer Volgograd, Thank you for your indifference =)

Answer 2

with a probability of 90%, the problem is precisely in the laser unit, it would be nice, of course, to have a donor for accurate diagnosis in the node, but judging by the anamnesis, the problem lies in the engine rotating the polygon - since after cleaning the polygon, any reasonable person will change the lubricant.
ps We do not pay attention to the problem of the photo shaft :)