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JLG 40E stuck in slow motion mode

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

  1. rookieatbest

    rookieatbest Active Member

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    I got my JLG 40E running great, but it now is stuck in slow motion mode again. Checked all limit switches, replaced with New batteries $$$$$..:( , replaced Sevcon board, replaced speed dial on platform, had right drive motor rebuilt $$$, and all boom functions move very slowly. My drive functions do not move at all. But this strange operation happens. For example if I'm in the boom and doesn't matter which operation I engage, as long as I press the steering button and a operation button it will immediately go into the faster mode like normal operation. To recap as an example, pressing the upper boom and the steering button it will move great. Or if I press the lower booms and the steering button the lower booms work great? Any thoughts?
     
  2. rookieatbest

    rookieatbest Active Member

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    really need some help trying to fix this? Could this be a issue with the change over contactor? I'm getting good voltages based on other threads in this forum that have had similar problems.
     
  3. 92U 3406

    92U 3406 Senior Member

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    We have a pair of JLG 600's that are electric and they behaved similar to that when the pump was on its way out. Functions were painfully slow but some would speed up if you toggled another function. If system pressure is low and the pump gets scorching hot, the pump is bypassing.
     
  4. rookieatbest

    rookieatbest Active Member

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    My drive forward and reverse are not working but all boom functions work, just very slow. Had both drive motors rebuilt and connected properly. I'm leaning towards the change over contactor not fully operating but they either work or don't work is my understanding. When the drive is engaged, the unit will click, click,click at the contactors and no movement in forward or reverse. When I press the steer and any other boom operation, it works fine??
     
  5. 92U 3406

    92U 3406 Senior Member

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    That's a strange one for sure. I'm not very familiar with your particular model but I would suspect your slow boom functions are more the result of hydraulics rather than electrical. The drive issue has me a bit puzzled though.

    Do you have access to a JLG Analyzer?
     
  6. willie59

    willie59 Super Moderator

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    If I'm not mistaken the 40E has electric drive motors. If that's the case, with you having problem with both drive not functioning properly and boom functions not functioning properly, the two are not directly related. The steer function Tee's off the same pump output line as the line that feeds the boom functions control valve. If you can toggle steering and make boom functions work somewhat better, disconnect the hose that feeds the steering valve and plug that hose, now see if your boom functions improve.
     
  7. 92U 3406

    92U 3406 Senior Member

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    That would make sense. I once had a 450AJ lose all toggle switch functions but if I ran the steering over relief, I would get the functions back. Chunk of an o-ring had jammed a two way check valve inside the hydraulic manifold.
     
  8. rookieatbest

    rookieatbest Active Member

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    Thanks for the help guys, I will attempt to plug the steering hose and see if that improves this weekend. Fingers crossed.
     
  9. rookieatbest

    rookieatbest Active Member

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    unfortunately I do not have access to a analyzer.
     
  10. Rick39

    Rick39 Active Member

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    The JLG analyzer does not work on the 40e with the sevcon.

    There is a "calibrator" that was used on them that had limited capability compared to the current unit introduced with the e series scissor lifts.

    If you changed the sevcon the new one might have some options set up incorrectly.
     
  11. 92U 3406

    92U 3406 Senior Member

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    That is good to know. I've never came across a JLG that wouldn't work with the analyzer so I thought it worked with all JLG equipment. Thanks for the info.
     
  12. rookieatbest

    rookieatbest Active Member

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    anyone want 10,000 lbs of scrap metal?
     
  13. Rick39

    Rick39 Active Member

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    Check your voltage at pin 4 orange wire on the sevcon, should be 48v from the elevation switches when in the stowed position.

    Also check pin 7 yellow wire, should be 48v when the unit is level.

    Pin 13 white/violet is the signal from the pump speed control and pin 14 white/black is the drive accel signal.

    Your issue is consistent with loss of level signal from the tilt sensor.

    I believe there is connector in the drive tray connecting the JLG harness to the Sevcon one and they would often lay in the bottom of the tray in a puddle of water and the pins would turn green.
     
  14. rookieatbest

    rookieatbest Active Member

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    Hello, the sevcon has different colored wires. The color of the wires do match on the connector connected to the side of the JLG rectangular motor controller and

    I get 46 Volt at pin 4 with foot on platform pedal and no function pressed
    0 volt at 7 with foot on platform pedal and no function pressed
    0 volt at 13 with foot on platform pedal and no function pressed
    4.1 volt at 14 with foot on platform pedal and no function pressed

    Thanks!
     
  15. Rick39

    Rick39 Active Member

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    OK, so your elevation switches are working but no signal from the tilt sensor.

    The tilt sensor has three wires, a hot and ground going in, and one with 48v out when the sensor is level. The wire colors at the sensor could be different but according to the print pin 1 on the connector white/yellow>green should be 48v+, pin 2 blue/red>white is 48v out when level, and white/brown>black is ground.

    The output from the tilt sensor also goes upstairs to the tilt relay to shut off the tilt alarm and light.

    Let's start with telling the sevcon the unit is level and go from there.

    BTW the manual is up on JLG's site on the public side.
     
  16. rookieatbest

    rookieatbest Active Member

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    Ok will test tomorrow rick, the mosquitoes are verocious out right now....
    I have the schematic manual but the quality of the diagrams are difficult to read. How may I find them on the public side?
    Ok I found the manuals..Thanks
     
  17. Rick39

    Rick39 Active Member

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    They are difficult to read.

    If you print them out sometimes you can fold an edge back and match it up to the corresponding page.
     
  18. rookieatbest

    rookieatbest Active Member

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    Unit is level with the bubble in the middle of the tilt sensor. We open the connector from the tilt sensor and measured 48 volts on pin 1 white/yellow. no voltage on pin 2 blue /red. Should we be reading the voltage with the connector connected to the tilt sensor at pin 1 or should pin 2 have voltage as well?
     
  19. Rick39

    Rick39 Active Member

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    Pins 1 & 3 should power up the sensor (hot and ground) and 2 should have 48v coming out of the sensor when level. Check for voltage between 1 & 3, should be 48V. Is the led on the bottom of the sensor lit up?

    You could try to jump power to the blue/red wire to simulate a signal from the tilt sensor that it is level.
     
  20. rookieatbest

    rookieatbest Active Member

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    I have the light lit up green on the bottom of the censor. The PIN number 1 + 3 does have power going in but I did not get power coming out. Power going in was 47 volts. I jumped Pin 1 and 2 as shown in the picture and ground connected.It is still moving in slow motion
     

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