Phaser 7760 blue bands / print quality

A Phaser 7760 has multiple lines on prints visible only when the dominant color on the page is cyan.

Lines are vertical (see attached) about 7-8 mm apart.

Though lines does not show/appear/obvious on CMYK prints (they are only visible on cyan dominant pages), the lines are actually quite faint it still does not pass the graphic designer's quality preferrence.

I already replaced the following parts, in order, still the lines are there:

*Developer assy & developers

*MOB Assy, transfer belt, and Laser

*MCU PWB

*Processor Board - this is the last i replaced yesterday but still no luck.

Any suggestions?