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Hitachi EX75UR

Discussion in 'Excavators' started by Dackdack, Oct 30, 2019.

  1. Dackdack

    Dackdack Member

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    Hey everyone, I’m having some electrical issues with my machine and I’m looking for a little bit of help. I have a late 90s hitachi ex75 ur grey market machine and it is equipped with the marccino system. When I fire the machine up i can operate all boom controls at a very low idle . Once I increase throttle the boom instantly locks out the boom up, boom down and boom in controls . The boom has a pivot point to allow you to dig on an angle and it also locks out one direction only. I’m certain it is electrical based on how sudden it shuts off and because if I hold the toggle switch behind the seat it appears to bypass this system and everything functions normally. Can anyone point me in the right direction to sort this issue out? Thanks very much
     
  2. uffex

    uffex Senior Member

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    Good day Back
    I suggest you appeal for a hydraulic schematic and wiring diagram that will enable us to help you and reduce the guess work.
    Kind regards
    Uffex
     
  3. Dackdack

    Dackdack Member

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    Ok thanks will do. Where exactly would someone find that info for a grey market machine?
     
  4. excavator

    excavator Senior Member

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    Can you post a picture of the machine and also a serial number? I'm not familiar with the "marccino system."
     
  5. uffex

    uffex Senior Member

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    Good day Dack
    The Marccino system was a type of leveling and depth control it was known to be be problematic and many have been by-passed, I'm not sure if that system is covered as well as Electric - hydraulic diagrams in the standard manual but check before you buy. I will check our archives if I find some useful info I will come back.
    Kind regards
    Uffex Untitled.jpeg
     
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  6. LACHAU

    LACHAU Well-Known Member

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    Full name is "AUTO MARCCINO CONTROL SYSTEM". The function of system is same as Mr. Uffex said above.

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  7. Dackdack

    Dackdack Member

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    Thanks very much for the info. Ideally I’d like to just bypass the whole system. Has anyone done this? Or know how I would do it?
     
  8. uffex

    uffex Senior Member

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    Good day Dack
    It has been done on home ground but we were not involved, we can steer you through the process if you are prepared to furnish us with photos etc.
    Kind regards
    Uffex
     
  9. completehydraulicstepuke

    completehydraulicstepuke New Member

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    Hi Uffex, as above, I would be VERY greatfull to you if you could steer me through the process of bypassing the marccino unit on a EX75UR-3 that I am working on. I have repaired sensors and diodes and it continues to be unreliable and drop out boom control. I have attached pictures. thank you in advance for any help.
     

    Attached Files:

  10. excavator

    excavator Senior Member

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    I've been dealing with the same system on an EX33Mu, I just didn't know that it was called the Marccino System. When the system was not working an alarm would sound continually and the boom up function would not work. All other pilot controls worked OK. I traced the boom up pilot line down from the controller towards the control valve and found it goes through the same solenoid block as the pilot shut off lines. I found a bad coil which I was not able to locate so I plumbed around the valve, removed the hose going in and connected it to the outgoing hose. So far it seems to work just fine.
     
  11. uffex

    uffex Senior Member

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    Good day Dack
    Sorry for delay in reply we have had some issues with our server and web site which has taken up some resources, however we are going to look into the issue deeper and will respond in due course.
    Kind regards
    Uffex
     
  12. LACHAU

    LACHAU Well-Known Member

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    If you need to bypass MARCCINO SYSTEM. Please try to using "EMERGENCY SWITCH" first.
    Then we will be talking about "BY-PASS" Proportional Solenoid Valve Block later.
    Good luck.

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  13. LACHAU

    LACHAU Well-Known Member

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    By-pass MARCCINO system by PSV block.

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  14. completehydraulicstepuke

    completehydraulicstepuke New Member

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    Many thanks uffex. Will let you know how i get on.
     
  15. LACHAU

    LACHAU Well-Known Member

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    be continued.
    How to "BY-PASS" MARCCINO system of EX75UR-3.

    EX75UR-3 BYPASS PSV 2.png

    EX75UR-3 BYPASS PSV.png


    EX75UR-3 main components layout.png
     
  16. Dackdack

    Dackdack Member

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  17. Dackdack

    Dackdack Member

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    Hey guys, I’m finally working on the issue. I cannot find or I am not sure where the 7 spool solonoid valve is. I have taken some panels off of where I thought it would be but this is all I see. Can anyone tell me if these two things are what I am supposed to be bypassing. Thanks
     

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