E061-0001 within canon imagepress c800

[khattab.al.masry]

Dears all:
we faced error code E061-0001 with imagepress c800 we replaced the following parts:
1-primary corona assy.
2-patch sensor for black drum
3-black drum with cleaner
but the error still as it
after researching we disabled potential sensor and that caused in error E029-421
so we want to know which is the cause?
thanks in advance.

[khattab.al.masry]

Engineers: any help

[charm5496]

are you sure that it is not an E029-4021?
If so then you need to look at the black drum drive coupler

[khattab.al.masry]

Thanks everybody:
the problem solved after cleaning laser unit for black.
thanks in advance.