Bizhub 501 Blank Copies

[emujo]

501 with 39K copies, original call was for lines in copies, looked like the drum was stalling slightly while image was being laid down. Previous tech replaced Drum, Dev Assy, x-fer sep corona assy, then dumped it in my lap. I pulled the boards out to look at the drive train for gear tooth broken etc, but found nothing out of sorts. Put MFP back together and started getting 6701/6702 codes. Replaced Sys bd, CCD flat cable scanner drive board with no change, changed PCRB and TADA, scan error is gone, MFP warms up and I do a test print. Blank copies, I mean polar bear in a snowstorm blank. Drum turns in load check. Replaced DC power supply, HVT and PCRB again with no change. I can see voltage on drum charge line, but since you have to remove develop cover to get to contacts MFP errors out with HVT code shortly. Drum coupling is fine, but replaced it anyway. I'm at a complete loss, any ideas? Emujo

[fixthecopier]

Sounds like you covered everything.

If there is no image on drum, I would take the drum unit to another machine. If it makes an image there, you have sn electrical problem, or a laser issue.

[emujo]

drum functions in another MFP. Swapped print head and no change. Nifty...Emujo

[Mr Spock]

Did you try memory? And the correct slot?

[fixthecopier]

At this point I would thing the boards are suspect. I would test them on a working machine. Were they new or repaired? I have been in a problem where I changed a board to correct a problem, and created another. If you are sure of the boards, then you may have to start looking for a pinched wire.

[Albonline]

think of 7145 what makes this happen there? shorted hv , try the white and red wires that run along the front of the unit have seen a few blow through the insulation and also the end contact points blow through.

[emujo]

I've verified that I have charge, sep and x-fer, blocked the charge corona with some paper, copies come out with the masked area black...I think I'm back to the SYS board, PRCB controls the poly motor and it's spinning. Think the SYS bd is not controlling the laser (print head). Wish the laser was in a visable range so I could tell for sure. Will post with any findings. Emujo

[wseyller]

I've verified that I have charge, sep and x-fer, blocked the charge corona with some paper, copies come out with the masked area black...I think I'm back to the SYS board, PRCB controls the poly motor and it's spinning. Think the SYS bd is not controlling the laser (print head). Wish the laser was in a visable range so I could tell for sure. Will post with any findings. Emujo

With most machines you would normally get at least a beam detect error if the laser didn't fire when it was suppose to. I would think an error would occur if this had happened.

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[Arcadian]

could be pressure roller or transfer rollers.

I would try to print something then ubruptly stop the machine then check the drum.

[emujo]

Come on guys, it's not my 1st day on the job here...sorry if I sound un appreciative, but that's like asking a guy with a flat tire if he's checked to see if there's air in the tire. If you've seen anything out of the ordinary that has caused this issue, I'd like to hear about it. You can bet that if it's happened once then it will happen again. Emujo

[fixthecopier]

I feel your pain. I have posted problems after I have done everything I could think of, and got no response or got people telling me to do basic stuff. Based on your first post, You just had lines until You pulled boards and ccd, and ribbon, ect. I used to get those codes, 6701 on Bz 500's, and reseating the ribbon would fix it. Based on what I have seen at my shop, were you swapping with used stuff. I have had techs "borrow" from a machine, and put the bad shit back on that machine and walk away.

You said you put the drum in another machine and it worked. I would be pulling all the stuff, ccd, ribbon ect. and trying them 1 at a time on that machine.

Please post when you fix it.

To give you an idea how funny those boards are, I recently had a 500 with a jam issue. I pulled and worked on the #2 feed system, put it back in and the bitch coded for something to do with the scanner board. Changed it, still dead. Long story short, machine is at shop, dead, I think we have it down to the epromm.

[dallas]

You're really sure the drum turns?
If not, check the Driving Unit Section, especially 50GA-1550 Dumper Plate Assy

[emujo]

ARRGH!!!! Still no success, but an update. Discovered through T/S process that my internal test prints will print fine though test mode. Gradiation patterns, and beam check all look good so at this point I have ruled out drum/developer, laser, HVT, DC power supply. R Ieplaced the SYS board (again) with no change. List Output, Printer test, sky shot, copies from glass, and ADF all blank. Panic stop shows nothing on drum (latent image). Did a initialization, no change. So WHY, DAMN YOU, wont you copy anything else????? Am I missing anything between the SYS bd and the laser unit? Even replaced the harness from the SYS bd to the laser. If I pull the connector from the PRCB I get a poly motor failure, C4401 if I pull the sysbd connectors I get C code so I know the board is looking for the correct feedback from the laser unit. Anybody need an anchor? Emujo

Update #2..Solved, it was the NVRAM. It was the only thing left to try...Emujo

[fixthecopier]

Thank you for posting the solution.

[blackcat4866]

ARRGH!!!! ...

Update #2..Solved, it was the NVRAM. It was the only thing left to try...Emujo

Thanks for sharing emujo. =^..^=