[CQ] Xerox WC 7855 Feeder Quality

[wertyxhts]

Hello,

I'm having an issue with a Xerox WC 7855(Firmware 72....)

1. Prints come out normal.
2. Scanning/Copying/Faxing on glass comes out fine.

However, when using documents on document handler (feeder), documents come out either almost blacked out or with rainbow colors. I've attached an example in this thread.

Any tips/suggestions are appreciated. Thank you.

[Phil B.]

Re: Xerox WC 7855 Feeder Quality

Hello, I'm having an issue with a Xerox WC 7855(Firmware 72....)
1. Prints come out normal. 2. Scanning/Copying/Faxing on glass comes out fine.
However, when using documents on document handler (feeder), documents come out either almost blacked out or with rainbow colors. I've attached an example in this thread.
Any tips/suggestions are appreciated. Thank you.

are you a tech

or end user? (suggest getting a service manual then)

I always start with power off..

disconnecting reconnecting all harnesses in the ADF to all interconnecting boards.

[wertyxhts]

Re: Xerox WC 7855 Feeder Quality

are you a tech

or end user? (suggest getting a service manual then)

I always start with power off..

disconnecting reconnecting all harnesses in the ADF to all interconnecting boards.

Tech.

Reboot fixes the issue for about a few minutes (2-5 minutes). But issue comes back with same symptoms.

Will be back at device tomorrow. I will reseat all connections and try f/w update.

[Richard.Xerox]

Re: Xerox WC 7855 Feeder Quality

Are those examples side 1 and side 2 of a duplex scan?

If so then on this model it's going to be faulty SBC or corrupt NVM. SBC is the only board the side 1 (via IIT PWB and Backplane PWB) and side 2 scan assembly (via Pyxis PWB) have in common.

Before changing any boards though head into diagnostics and initialize the scanner NVM. SBC replace as a last resort.

[wertyxhts]

Re: Xerox WC 7855 Feeder Quality

Are those examples side 1 and side 2 of a duplex scan?

If so then on this model it's going to be faulty SBC or corrupt NVM. SBC is the only board the side 1 (via IIT PWB and Backplane PWB) and side 2 scan assembly (via Pyxis PWB) have in common.

Before changing any boards though head into diagnostics and initialize the scanner NVM. SBC replace as a last resort.

When duplex scanning, only first page has defect. Second side comes out okay.

Initialized scanner NVM. Also re-seated connections. Still same issue.

Would you happen to have the part number?

[Richard.Xerox]

Re: Xerox WC 7855 Feeder Quality

Ok if its only 1 side affected then its not the SBC. more likely the IIT PWB or Pyxis PWB depending on which side has the issue.

Write 1 and 2 on opposite sides of a sheet of paper and copy duplex through the dadf with the number 1 facing up.

If the number one side is bad but 2 okay its the IIT PWB. If the number 2 comes out bad but 1 ok its the Pyxis PWB.

Part numbers:

Pyxis PWB: 604K89991
IIT PWB: 960K61760

*EDIT*

I've read you first post again and noticed you say its fine from the glass. That rules out the IIT PWB and leads me to think its the Pyxis PWB which sits on the back of the SBC tray (3 thumb screws and slides out as a unit)

[wertyxhts]

Re: Xerox WC 7855 Feeder Quality

Ok if its only 1 side affected then its not the SBC. more likely the IIT PWB or Pyxis PWB depending on which side has the issue.

Write 1 and 2 on opposite sides of a sheet of paper and copy duplex through the dadf with the number 1 facing up.

If the number one side is bad but 2 okay its the IIT PWB. If the number 2 comes out bad but 1 ok its the Pyxis PWB.

Part numbers:

Pyxis PWB: 604K89991
IIT PWB: 960K61760

*EDIT*

I've read you first post again and noticed you say its fine from the glass. That rules out the IIT PWB and leads me to think its the Pyxis PWB which sits on the back of the SBC tray (3 thumb screws and slides out as a unit)

Thank you Richard, will look into this. I will update with results.

[MrXerox]

Re: Xerox WC 7855 Feeder Quality

Thank you Richard, will look into this. I will update with results.

Let me know if you need a quote on any parts, we have a pretty vast parts dept with pulled used, tested working parts.


Sent from my iPhone using Tapatalk

[wertyxhts]

Re: Xerox WC 7855 Feeder Quality

**UPDATE**

Replaced the Pyxis PWB. Same result.


On DADF using duplex, side 1 has same issue, side 2 comes out okay still.

On glass, copies are shifted about 1/2 inch to the left and is a lot lighter than going on the DADF.

Thinking about replacing IIT PWB / SBC. Thoughts?

[Richard.Xerox]

Re: Xerox WC 7855 Feeder Quality

In Diagnostics try performing white reference setup, run the paper through three times each for DADF and scanner, i'd be interested to know the results of the 3rd pass.

It could be the side 2 scan assembly inside the DADF, not had a bad one yet on these machines but theres always the posibility.

After ruling out the Pyxis, the only other parts related to scanning are the IIT PWB, Backplane PWB and SBC.


Start with IIT PWB, remember to move the EEPROM chip from the old board to new one though unless you have a new chip.

[Scarecrow]

Re: Xerox WC 7855 Feeder Quality

wertyxhts, What occured just before this problem started? With glass registration off - this throws another clue in the mix. My guess is if reg were right, your issue would go away because side 1 is using the glass (and associated optics) and side 2 uses the dh for initial processing of side 2. Side 2 is ok. The dh is fine. Something is probably wrong with the optics, or optics control, in the scanner. When using the dh, the optics move to the left, and are probably out of range of the paper on the scan glass, meaning the scanner sees something other than the moving paper, and this is probably giving the rainbow effect. Is the plastic light tube in place? Somebody fooling with the mirrors or ccd? Drives ok? NVM changed? Interesting problem.

Edit: After reading your first post, you say the prints are fine for a few minutes. Does that mean if you make 200 copies the end copies are rainbowed? Or are you running several originals and then the problem occurs? Is the registration fine initially and then tapers off?

[wertyxhts]

Re: Xerox WC 7855 Feeder Quality

wertyxhts, What occured just before this problem started? With glass registration off - this throws another clue in the mix. My guess is if reg were right, your issue would go away because side 1 is using the glass (and associated optics) and side 2 uses the dh for initial processing of side 2. Side 2 is ok. The dh is fine. Something is probably wrong with the optics, or optics control, in the scanner. When using the dh, the optics move to the left, and are probably out of range of the paper on the scan glass, meaning the scanner sees something other than the moving paper, and this is probably giving the rainbow effect. Is the plastic light tube in place? Somebody fooling with the mirrors or ccd? Drives ok? NVM changed? Interesting problem.

Edit: After reading your first post, you say the prints are fine for a few minutes. Does that mean if you make 200 copies the end copies are rainbowed? Or are you running several originals and then the problem occurs? Is the registration fine initially and then tapers off?

After reboot or waking up from sleep, device scans/copies fine. About 10 copies/scans. Then the issue returns.

[Scarecrow]

Re: Xerox WC 7855 Feeder Quality

Does that mean your registration is fine initially?

[wertyxhts]

Re: Xerox WC 7855 Feeder Quality

SOLVED! Forgot to update a few months ago. This was a weird one. I replaced the pyxis card on this, and that did not solve issue. I tried SBC next w/ firmware update, but that did not help either. I was getting ready to replace IIT board, as I opened the DADF cover, I noticed the motor was not seated correctly. It was falling off its bracket. I ended up super gluing it and that resolved issue.