Toshiba E-Studio 311c Magenta Background

[tinnyjay]

Hello!
We have a Toshiba E-Studio 311c and it had proplems with background.
First,all the background was filled with cyan toner and after replacement of drums, coronas,
developers,it prints a dirty backround of magenta.There is no cyan on background,but now is magenta.We changed drum,developer,corona, and still the same thing.
There are 4 techinians working on this,and still nothing.Here is the test
Page0001.jpg

Somebody helps me please.

[Mr Spock]

check the erase lamps and the main charge for the magenta drum is seated correctly.

[tinnyjay]

check the erase lamps and the main charge for the magenta drum is seated correctly.

After i activated all Image Quality Sensors(08-400-401...etc),i just did a calibration and the test was ok,but after printing from pc it printed a blue background and sometimes a yellow background.
I just take list prints from another Toshiba E-Studio 311c (it is perfect) and i am entering in my 311c to see what will happens.

[jamesyboy]

switch off iqc and try swapping around 2 colours looks like an epu fault ! drum earthing