Magenta toner on 8550GN offset to the right of the page

[Wurzel.D]

My 8550GN is printing roughly every 4th page of colour with the red (magenta) offset to the right by about 15mm. So any pictures or text that contain red colours have a weird red or pinky shadow 15mm to the right. Has anyone had the same problem??? We've given it a new drum kit, cleaned the internals and replaced the red toner but still no joy! HP werent much help either, i think the best bit of advice they gave me was to buy all new internals from them which was just a blatant advert and at those prices i might aswell have bought another printer! Please help, before i go mad trying to fix this troublesome machine and break out the sledge hammer! Any help much apreciated guys, you will be saving my (and the printers) life.

[MichaelTech]

Color plane registration.
Check the green handle, to ensure it is correctly locked in. It can rotate on it's rod if pushed too hard.
Check Transfer drum guide for cracks.
You will need a PEP Kit. RG9-1495-000CN Instructions included.
Check tha last two digits of the engine settings 1&2 in service mode. Compare to tags inside front door.
Do the Color Balance Adjustments. Press GO and -Value+ at the same time.
Print an adjustment page, and make changes to each color.