When to replace?

[Litz!12]

What is the job of Xerox Registration Transport Assembly & MOB Sensor Assembly? what do they do?

[slimslob]

Post your question in the correct forum. https://www.copytechnet.com/forums/xerox/

[blackcat4866]

You might also include some specific information, like:

What model Xerox that you have?
What sort of problem that you're having?
and why you suspect these items?

You'll probably get more useful information. =^..^=