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  1. #1
    Trusted Tech 50+ Posts CKiiza's Avatar
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    C451 spoiling Imaging Units

    Hi Engineers,
    I need you to help me understand this so I can give a sufficient solution to my client.

    About 4 months ago this Machine started spoiling imaging units. The black IU first had issues with the developer spilling out on prints, then the image started to gray out(fade) along specific areas on the print which appeared to be due to poor charging. The Unit was replaced and the replacement worked well.
    then the fading started in Yellow IU and a tech of mine went and solved it(by some miracle according to him.) The client then ran about 600 copies of books of roughly 80-100 pages each and the next thing I knew was that Y,M,C Units were completely spoilt out of the fade effect. They were all replaced and the machine worked well. I've been informed that the Black unit also ended up dead a few days later and was replaced again.
    Now the Yellow unit has faded again and I'm suspecting the High Voltage Board though I'm thinking the problem stems from the volume of work this client is doing in a single printing period.
    Thanks so much for your help


  2. #2
    All things Konica Minolta 1,000+ Posts Stirton.M's Avatar
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    There have been a rash of bad IUs lately I've noticed...though I doubt this is related to your problem.

    However, you may be right about it being an HV bias related issue. There are a few modification here and there to fix the issue. Mostly to do with modifying the lock tabs for each IU. In one case, the modification is semi-permanent, meaning a bracket and screw are put in to lock the tab itself in the closed position. Another modification would be to use a foam or rubber spacer on the tab to push the IU into the machine with a little more force. It does not have to be very thick...just enough to keep the IU from "walking" as it turns, which more often than not can cause the bias problems you described above.

    Others here may have more ideas for you.....

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  3. #3
    Technician krazeekidz3's Avatar
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    I've been having the same sorts of problems on a C550. This machine is also doing a very high volume. Maybe even more that the machine can handle. I've been sending IU's back to KMBS left and right! The warranty program is very helpful! I'd like to know if anyone has any tips or solutions.
    Thanks!!!


  4. #4
    Gimp 500+ Posts JSC's Avatar
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    I have had a few of these and they have all been down to the IU's not having a very good bias connection, and as Stirton.M has said you can get the mod iu locks, but I have just used a bit of packing to help keep the iu that bit more secure. Has worked well so far


  5. #5
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    Remember the 7060 b&w, the developer would wear out in half the time if you ran high volume. It like over heated or beat itself to death.
    I think I am having the same probem in the in the bizhub C350.


  6. #6
    All things Konica Minolta 1,000+ Posts Stirton.M's Avatar
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    These colour image units have a finite life, depending on the machine model and colour vs black, typically from 30K to 120K...problem is, they are dying earlier than they should and more often than not, it has more to do with developer bias issues than volume. They can go south within days of being replaced.

    "Many years ago I chased a woman for almost two years, only to discover that her tastes were exactly like mine: we both were crazy about girls."
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  7. #7
    Vulcan Inventor of Death 1,000+ Posts Mr Spock's Avatar
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    I have one that is eating yellow units every other week. SSD is telling me to check the connections on the back of the unit and replace the hv1 pwb. Will update when the board comes in. (ordered 10 days ago).

    And Star Trek was just a tv show...yeah right!

  8. #8
    Service Manager 100+ Posts
    C451 spoiling Imaging Units

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    i had same problem as Mr Spock eating up yellow IU , i took of both hv boards and reseted the hv contacts(springs) that make contact with IU's ,and so far machine has been ok for last 3 months

    If at First you don't succeed remove all evidence of ever trying!

  9. #9
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    Got it, I will check this out.

    Thanks this could help my c350 problem.


  10. #10
    All things Konica Minolta 1,000+ Posts Stirton.M's Avatar
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    Quote Originally Posted by Mr Spock View Post
    I have one that is eating yellow units every other week. SSD is telling me to check the connections on the back of the unit and replace the hv1 pwb. Will update when the board comes in. (ordered 10 days ago).
    Depending on which model you are working with, some can be fixed by simple measures. Remove the HV board....that is the hard part...

    Resolder all the HV coil points, as well as the wire connects of the board. Cold solder can cause issues here in the same manner.

    And in the case of the C350, and I think a few other machines (cannot recall of the top of my head)...that the board is screwed into place with the contacts to the HV connectors at each screw point, the amount of solder making a connection to the tin conductors the board is screwed to is not enough. I physically solder those little "star" type lock washers to the underside of the board to make sure the contact bites into the tin when put back in the machine. This has helped a few times.

    Last edited by Stirton.M; 09-30-2010 at 01:40 AM. Reason: wrong machine quoted originally.
    "Many years ago I chased a woman for almost two years, only to discover that her tastes were exactly like mine: we both were crazy about girls."
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    Please do not PM me for questions related to Konica Minolta hardware.
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