Ricoh 4015 black copies

[tonyadf]

Iv'e got a Ricoh 4015 giving black copies. Optics are ok, i have changed the drum / dev assembly and even the main board. I had a similar problem a while ago with a different machine and that was a bad dev bias connection but it seems ok here.
Bright ideas welcome

[copi_40]

Complete black ?
I had once a very strange behavior caused by ozone fan . Also check filter .

[tonyadf]

Completely black copy, sometimes putting dev on copies

[Kopyrtek]

Check the 4th and 5th mirror position and also your drum ground.If that doesn't get it,could be the drum unit itself.

[tonyadf]

Thanks for your help guys, it was a poor drum earth, everything fine now.