DC250 / 76xx dark band lead-edge to trail-edge

[Caffeine]

I've bumped into a real stumper, maybe someone has some experience with this?

I've attached an image. The band is just above the "rear of machine" notation. The uneven darkness at the bottom of the image is just my shadow... haha

I've got a LE->TE band, in cyan ONLY. It basically just intensifies any cyan in its path, if there is no cyan in that area, there is no band.

At first I thought it was something simple, but I've eliminated all the usual suspects, and now I'm at a loss.

So far, the following had NO effect:

- Replacing the drum
- Replacing the whole cyan developer unit
- Swapping the erase lamp with another color position
- Cleaning the CK ROS
- Cleaning the 1st BTR rollers in the belt assembly

What I haven't done, since it affects cyan only and no other colors, is mess with the fuser, 2nd BTR, belt cleaner or belt itself.

I also haven't swapped the CK laser unit from another machine, because I hate digging in to a good working machine (and my only backup at the moment) for the ROS units. Those flat foil cables SUCK.

Just in the process of typing this, one test I realized didn't do which I could pretty easily is swap the 1st BTR's inside the belt unit. I could swap the cyan and magenta to see if perhaps the 1st BTR is bad. I'll report back on that.

Does anyone else have any experience with a band like this?

Thanks!

[Caffeine]

Re: DC250 / 76xx dark band lead-edge to trail-edge

Swapping the entire belt assembly with a known good unit had no effect. So it isn't there either.

[adriansto]

Re: DC250 / 76xx dark band lead-edge to trail-edge

Do you change drum or drum module unit?

[Caffeine]

Re: DC250 / 76xx dark band lead-edge to trail-edge

Do you change drum or drum module unit?

Complete brand new authentic Xerox drum. (I don't bother with remaning the drums on this machine...)

[adriansto]

Re: DC250 / 76xx dark band lead-edge to trail-edge

On IBT appear same band ?

[Caffeine]

Re: DC250 / 76xx dark band lead-edge to trail-edge

On IBT appear same band ?

Yep, it is being imaged that way.

[kalindd]

Re: DC250 / 76xx dark band lead-edge to trail-edge

I can not see it clearly on your scan.
Is it fading form front to rear side and then suddenly gets darker?
If this is the case, I've seen it in the past.
100% ROS unit, but back then changing or cleaning the ROS fixed it.
I see that you have already tried this. So I can only suggest you to find a new ROS unit and try again.
Can you please take a pic at the ROS unit when it is disassembled and post it here, so I can mark which mirror is the problem.
Greetings.

[adriansto]

Re: DC250 / 76xx dark band lead-edge to trail-edge

In this case is time to change the CK ros assy.
Go to DC612 and print cyan Ros halftone pattern and compare with K,Y,M ros halftone.
But you can try to remove the ros, clean it also clean the flat cables and connectors in MCU, and see what is happen.

[Caffeine]

Re: DC250 / 76xx dark band lead-edge to trail-edge

Yeah, I guess the ROS is all that is left... I cleaned the CK ROS well (I've cleaned the ROS units on these machines many times, so I'm pretty good at doing it 'right'...) I have another machine which a good CK ROS which I can swap to see if that fixes it.

But first I will clean the flat foil cables connected to the MCU... (They are easy to get to.) Then, if that doesn't work, I will open it back up to clean the foil cables on the connection to the ROS. If that doesn't work, I'll open up the other machine and 'borrow' its ROS.

What is your preferred cleaner for the flat foil cables? Alcohol?

Thanks for the help guys!

[Caffeine]

Re: DC250 / 76xx dark band lead-edge to trail-edge

I can not see it clearly on your scan.
Is it fading form front to rear side and then suddenly gets darker?
If this is the case, I've seen it in the past.
100% ROS unit, but back then changing or cleaning the ROS fixed it.
I see that you have already tried this. So I can only suggest you to find a new ROS unit and try again.
Can you please take a pic at the ROS unit when it is disassembled and post it here, so I can mark which mirror is the problem.
Greetings.

Right above where I wrote "REAR OF MACHINE" on the printout, there is a lead edge to trail edge dark band, about 1" wide... It is pretty even throughout the print, except that 1" band.

[adriansto]

Re: DC250 / 76xx dark band lead-edge to trail-edge

What is your preferred cleaner for the flat foil cables? Alcohol?

Thanks for the help guys!

I use contact cleaner spray for electronics components, or isopropyl alcohol.

[kalindd]

Re: DC250 / 76xx dark band lead-edge to trail-edge

Right above where I wrote "REAR OF MACHINE" on the printout, there is a lead edge to trail edge dark band, about 1" wide... It is pretty even throughout the print, except that 1" band.

I'm pretty sure it's the ROS.

[Ianizer]

Re: DC250 / 76xx dark band lead-edge to trail-edge

How are you generating your test pattern?
-I

[bojans]

Re: DC250 / 76xx dark band lead-edge to trail-edge

I've had this problem before. It was ROS.

[Caffeine]

Re: DC250 / 76xx dark band lead-edge to trail-edge

I've had this problem before. It was ROS.

Did you have to replace it? I cleaned it well, so I don't think cleaning it will fix it. I didn't clean the foil cables, though, so I will try that. But in your case, did you have to replace it? Thanks!