Bought a Dell 2155cn Colour Laser but print fading on one side?

[madesimplemedia]

Hi

I bought a used Dell 2155cn Colour Laser but print fading on one side. I have done drum and toner refreshes etc, tried different toner but it is still faded to one side of the paper.
What can I try next?

Thanks
Dave

 

[madesimplemedia]

Changed the PHD on it, still bad. I wonder if it's a roller or something?