Hello,
How many copies do You have? ( press 123 button )
If You have over 150 000 copies, probably you need to change the Bk developer unit. It can't be changed only the developer, but the whole unit.
This is quite expensive copier for maintenance. If the time comes for Bk developer unit it means that you will soon have to replace Y, C and M developer unit. Also when did you last time replaced the drum unit?
Be sure to post back the copy counter, for detailed instrunctions...
Regarding color adjustment, before that you need to clean the copy optics ( glass beneath and cis sensor ), then in user mode ( asterix key ) under copy settings find color adjustment and perform it.
It's like 5 sheets, beeing printed one by one and which you need to scann over copy glass, but in most cases it doesn't helps...
If You want service manual you can write on
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