BizHub C203 print white page!

[furius]

Hi guys,
I have a problem on an old c203.
The machine made strips of black, I replaced the IU K.
The problem has been solved.
After a week the customer calls me and says that the machine prints completely blank, both in copy and in print.
The machine does not emit any noise , and does not give any error code
I thought of the MFB or the laser card.
The customer is distant and in a few days I will go to do the surgery.
I have another machine to take spare parts from.
You can give me some advice
THANKS GUYS

[allan]

Look if there is an image on the transfer belt if you stop the machine mid print.
The transfer roller retraction gets goofed up on these machine so that the transfer roller is not pressed against the belt.