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JLG 40E stuck in slow motion mode

Discussion in 'Other Construction/Demolition Equipment' started by rookieatbest, Feb 23, 2017.

  1. Rick39

    Rick39 Active Member

    Joined:
    Jan 7, 2017
    Messages:
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    Location:
    SE PA
    Do you now have 48v at pin 7 yellow on the sevcon?

    If so check pin 13 white/violet with a boom function engaged and vary the boom speed knob.

    That will tell us if the sevcon is seeing the boom speed command.
     
  2. rookieatbest

    rookieatbest Member

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    Location:
    Tampa
    Yes, I am getting 47V at pin 7 yellow. When I engage a boom function at pin 13 with the speed control knob at the detent I get 2 volts. As I turn it clockwise (speed up control knob) the voltage drops from 2 volts slowly down to 0 volts when the speed knob is all the way fast. If I stop the speed knob half way between slow and fast it will remain at around 1 volt give or take.
     
  3. Rick39

    Rick39 Active Member

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    Location:
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    We're making progress. If the unit was working correctly the boom functions would go into creep mode when above elevation and tilted.

    Does the pump speed knob have any affect on the boom speed?

    I'm not sure what the speed signal should be at pin 13 other than it comes from pin 2, up through the pot, then back down to pin 13. With the pot fully clockwise the reading should be the same at 2 and 13.

    I had a cheat sheet from when the 30E first came out but that's long gone.

    What is the voltage across the battery pack?
     
  4. rookieatbest

    rookieatbest Member

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    Across the battery pack we are getting 47.5 volts
    Yes the pump speed knob works but it is still in a lethargic mode. When turned to the slowest setting the booms barely move if at all. When the speed knob is turned to the fast setting the booms lift but very slowly as if it were in a creep mode but as soon as you press the steering function either left or right, the booms kick into normal high speed operation.

    With the platform foot switch pressed and no other functions activated, we get 2 volts at pin 13. When you turn the speed knob this volts progressively lowers down to zero. It progressively increases back to 2 volts when turned the opposite way.

    I will have to try pin 2 tomorrow am as a massive thunderstorm is approching.
    We truly appreciate the effort to fix this and we will compensate you once its running. Thanks again
     
  5. Rick39

    Rick39 Active Member

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    Location:
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    Can you plug it in?

    47.5 volts is nearly dead. Fully charged resting voltage should be 50.4 and will approach 60 as the charger is finishing up.
     
  6. rookieatbest

    rookieatbest Member

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    Location:
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    Haven't charged in a week but will place it on charge. Replaced 4 batteries and prior to the replacement was getting 38-41 volts. It actually was working fine even back then. I've lifted the steering wheels to get a full turn left to right or right to left and the unit still will 'kick" into normal operation at the 47.5 volt when the steering wheels turned and a boom function in operation.
    Will charge over the weekend and retest the above procedures again.
     
  7. Rick39

    Rick39 Active Member

    Joined:
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    Location:
    SE PA
    When you activate steer a contactor puts full power to the pump motor bypassing the sevcon.

    When operating normally the sevcon meters the current going to the motor.

    Some of these had low voltage protection built into them.

    You may want to check the individual batteries and charge some individually or in pairs if they are out of balance, also check the pack voltage under load.
     
  8. rookieatbest

    rookieatbest Member

    Joined:
    Nov 29, 2014
    Messages:
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    Location:
    Tampa
    Charged over the last few days. Problem still acts the same.
    Battery 1. 6.56 v
    2. 6.31
    3. 6.78
    4 . 6.27
    5. 6.96
    6. 6.81
    7. 6.70
    8. 6.54

    Will attempt the procedures above again.