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JLG 600A stuck in turtle / creep mode

Discussion in 'Forklifts/Telehandlers' started by kapope712, Jan 29, 2020.

  1. kapope712

    kapope712 Member

    Joined:
    Mar 14, 2017
    Messages:
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    Location:
    Pipersville, PA
    Working on my 97 600A with Deutz. It seems that my travel and possibly my control speeds are stuck in either creep mode or turtle (if there’s a difference). Throughout different movements and switchology I can hear the 3 different RPM ranges that the MX manual mentions.

    I’m new to this machine and been going over some issues with it. I found what I believe to be the boom level sensor unplugged. I thought maybe this was the issue but after plugging it back in there was no change (the manual states anytime the boom is above the horizon the machine will creep).

    Thoughts on the sensor just being bad? Is this switch normally open or closed? Can I jump it for Diagnosis purposes ONLY? Or should I look in some different places?

    Any help would be much appreciated!!!
     
  2. Mikefromcny

    Mikefromcny Well-Known Member

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    Occupation:
    Mechanic
    Location:
    Upstate NY
    Check your proximity switches. Sounds like 1 is stuck.
     
    92U 3406 likes this.
  3. Txhayseed

    Txhayseed Active Member

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    Dec 23, 2019
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    Location:
    Texas
    You have one limit switch on the boom extent retract and one for stowed drive that control drive speed control. One could be stuck or bad. Do you have a hand held analyzer ?
     
  4. kapope712

    kapope712 Member

    Joined:
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    Location:
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    Thanks for the replies. I have visually inspected all of the switches and they seem to function correctly (externally).

    I do not have an analyzer, will the analyzer work on a 1997?

    I have attached an excerpt from the maintenance manual regarding the limit switches. Which switch would be the one possibly limiting the travel speed?
     

    Attached Files:

  5. Txhayseed

    Txhayseed Active Member

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    Check your horizontal limit switch. And the boom extend retract limit switch. Those are the two that tell the machine your out of trasport mode and to reduce drive speed. Are all your other functions stuck in creep to ? Like lift, basket rotate etc. Or just drive when stowed ?
     
  6. kapope712

    kapope712 Member

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    Location:
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    I will look further into the switches. I know the boom extend/retract switch is working because I get the 1000lb/500lb platform limit light at the platform control panel. Which switch is the “horizontal”?

    I’m new to the world of boom lifts but to me everything seems slow. It’s as if the speed rheostat on the platform control panel makes no difference when operated.

    Thank you.
     
  7. Txhayseed

    Txhayseed Active Member

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    The platform dial controls functions like basket tilt, rotate , jib etc.. the rheostats them selfs do fail and its common. I replace alot of them from people wrenching down on them and simply breaking the internal works. I think your on track with the limit switches causing your stowed drive speed beeing slow.
     
    kapope712 likes this.
  8. kapope712

    kapope712 Member

    Joined:
    Mar 14, 2017
    Messages:
    7
    Location:
    Pipersville, PA
    Okay, I am pretty sure I have the limited travel speed pinpointed to the lower horizontal limit switch seen in the attached picture. It seems to me that it’s always activated with the way it’s currently mounted.

    I took it off and I get a much faster travel speed after I turn the control speed rheostat to anything other than turtle.

    The rheostat does however seem more like an on/off switch vs. the way a rheostat “should” work. Whenever I dial the rheostat to anything other than turtle the green snail light comes on and stays on; this doesn’t seem normal to me?

    How should the lower horizontal limit switch be mounted?

    Thoughts on the rheostat being worn out or wired wrong? Should this rheostat have any control of travel speed at all (its a 1997)?

    Thanks!
     

    Attached Files:

    Last edited: Feb 27, 2020 at 3:48 PM
  9. Txhayseed

    Txhayseed Active Member

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    The rheostats is like that even when its new. It really does not ever seem to change much unless you have it dialed one way or the other. There is really not a middle ground.
     
  10. Txhayseed

    Txhayseed Active Member

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    Messages:
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    Location:
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    The limit switch should activate as it rotates around the boss. The pin boss is actually the eccentric that actuates the switch. Id open it up and see if the plunger is working or broke. We replace alot of limit switches. The get stuck/ broke and contacts just fail.