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Hitachi EX60 URG need electrical diagram

Discussion in 'Excavators' started by allpinball, May 18, 2010.

  1. allpinball

    allpinball Member

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    No prior electrical problems but now the starter (key) switch produces nothing. Turning the ignition on lights the dash lights and the fan and other accessories work.

    I can engage the starter by jumping the high-amperage solenoid located just inside the engine door and putting +24v to the white-red wire (running to the starter solenoid) on the same unit. So the starter and it's interconnecting wiring is all functional.

    If I could find a wiring diagram showing the basic pieces and wire colors of the starter circuit I could trouble shoot it much easier. Anyone have a service manual handy, or at a minimum can describe what I should see (i.e., measure) happening at the solenoid when the key is turned to start?

    I also find it odd the heavy red wire which is ultimately switched to the white-red on the small side of the solenoid has no juice in it...so even if the solenoid did engage, it has no _24v to send to the starter. I have a feeling the lack of +24 at the red wire is part of my problem.
     
  2. Aardvark

    Aardvark Well-Known Member

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    24 volts?

    Don't catch it on fire or melt the harness mate.
    It's a 12 volt system.
    Did you say there is no power at the main wire at the starter. Should be 12V all the time.
    Get a multimeter and check both ends for a start :drinkup
     
  3. allpinball

    allpinball Member

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    yes, 24v

    No question it is 24 volts; (2) 12v batteries in series. It's a grey market machine, isuzu diesel, if it matters....

    There is battery power to the starter solenoid, and it'll crank if I jumper the solenoids. Problem is the solenoid has 1/2 dozen low-amperage inputs going to it, so I need to know what to test for to see why the key switch is not activating it.
     
  4. machine

    machine Well-Known Member

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    If your unit is the same as the larger Hitachi I believe you are describing what they call a safety relay. It prevents the starter from engaging if the engine is already running. Also it disconnects the starter once the engine starts. It does this by a signal from the alternator. The regulator in the alt. can fail a diode and and the voltage leak will make the safety relay prevent the starter from working. There should be only two wires from the main harness that activate the safety relay. One will be the signal from the key switch. The other will be the signal from the alternator. you can test it with a light or a volt meter. Also be aware that there could be two fuses (fusible links) usually at the electric battery disconnect. One is live with the key off the other is live with the key on.
     
  5. allpinball

    allpinball Member

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    still looking

    my starting problem likely resides in the starter safety relay - I really need a wiring diagram to trouble shoot. Does anyone have a scan of the starter electrical diagram for any similar sized hitachi EXxx? This is a mid-90's machine w/the isuzu diesel engine. there was an ex200 starter diagram posted here earlier but too fuzzy of an image to read.
     
  6. -3Doc

    -3Doc Well-Known Member

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    Try this it is for an ex100 hope this helps!:)
     

    Attached Files:

  7. allpinball

    allpinball Member

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    thanks -3Doc

    thanks for the ex100 diagram....the basic components and # of wire connections & their letters at each component look equal to mine...from memory anyways. I'll compare it to the machine tonight.

    Kind of curious what's meant by the "load damp relay"? It looks like it's purpose is to keep the battery relay energized (via a signal from the alternator) if the engine is still running even if the key switch is turned to off?
     
  8. -3Doc

    -3Doc Well-Known Member

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    You are right that is exactly what it does, then as soon as the engine stops it "dumps" the load on the electrical system.:)
     
  9. maxa

    maxa New Member

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    did you ever figure it out?

    Looks like I have the same problem with the same model excavator. Did you ever figure out what was wrong?
     
  10. chuck767

    chuck767 Active Member

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    I have the same problem with the same model. What was the solution?
     
  11. maxa

    maxa New Member

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    fix

    In my case the starter solenoid was burnt out. It took me a while to figure out how it got damaged. Here's what I found (with the help of the above ex100 diagram which is close enough for the ex60urg):
    - The excavator hadn't been used for a while and the ignition lock had started to seize
    - I started the engine and drove away, not realizing that the key was stuck in the START position, it hadn't returned to RUN by itself
    - There's a circuit (safety relay, see machine's post above) that cuts off the starter once the engine (alternator) is running but in my case the alternator belt had come so loose the alternator didn't spin and therefore didn't cut the starter
    - I drove the excavator for 20 mins and during that time the starter motor must have been running and the solenoid was engaged the whole time which caused it to burn out and seize

    I got a new starter off ebay (~ $150 iirc) and managed to put it in without dropping the engine but it was still a pita. And yes, I replaced and tightened the belt (batteries are charging now, nice). And lubed the ignition lock.

    Btw, big thanks :thumbsup to everybody who posted information on this thread. It allowed me to fix the ex myself for cheap instead of paying big money to have someone come out and repair it.
     
  12. chuck767

    chuck767 Active Member

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    Thanks Maxa,

    I think my problem has something to do with the safety relay. I have a boat with Hino diesel engines and had a similar problem and it was the safety relay. Ironically my alt is not charging and I need get that addressed too. Wish it was just the belt but I think it is something more serious.
    Regards,
    Chuck
     
  13. tomorrow 22

    tomorrow 22 New Member

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    Hi i have ex100-2 that doesnt turn off with the key any ideas? if i turn it off then unplug the alternator it will stop. or if i cut the blue-yellow wire it will stop can i just wire the blue-yellow straight to alterntor waring light
    chhers for any help
     
  14. TomD

    TomD New Member

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    hi there I know this is an old topic but I have an ex60 with nissin engine, it is not charging, light goes out on dash when engine is started but less than 24volts at battery, also when you switch off ignition, lights are still on dash and buzzer sounds!? and the large contactor next to the batteries is still energized but if I pull the T shaped plug with two wires out the back of the alternator this cuts the power to contactor and all lights and buzzer go off as they should, is this an alternator fault or does this machine have the load damp relay as wiring diagram above??
    thanks for any help that can be given..
    Tom.
     
  15. David gladwyn

    David gladwyn New Member

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    Hi Tom I Have almost an identical problem on my EX60 except the alternator light doesn't work at all. Have you fixed It yet.... cheers Dave
     
  16. TomD

    TomD New Member

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    not yet Dave, going to have a look at it today will let you know what I find..
    cheers Tom..
     
  17. 007

    007 Active Member

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    Hi Guys, I might be able to help you.
    I was not here when this thread was posted but the guys got most of it right trying to work out there problems.
    The diagram above is very fuzzy and hard to see things but i have worked most of it out.
    The wording is miss leading but what ever.
    Why the (load damp relay) its actual function it to maintain a connection from the output of the alternator to the battery's at all times the engine is running as the alternator can be damaged if run with no output.
    The Safety relay primary function is a starter relay with start inhibit function if the engine is running.
    So this is where it gets tricky and is that diagram exactly the way your machines are wired.
    For example typically the alternator warning light is used to excite the alternator to get it up and running each time the engine is started.
    In that circuit shown there is no warning light and the alternator is excited using a resister shown on the back of the alternator near the plug.
    In this circuit the Safety Relay, Load Damp Relay, and CPU are sensing the excitation voltage from the alternator and presumably the cpu is controlling the alt warning light in the cluster.
    The only part of the circuit i haven't figured out is the stop function from the key.
    With Regards to tomD machine I would guess your alternator is fine.
    What you are describing all of the relays are doing what they are supposed to be doing.
    Am i to assume the engine does not stop when you turn the key off??
    Regarding the charging my first look would be at a loose fan belt as the alternator can create the right voltage to trick all the relays but still not delivering current to the battery's to lift the voltage.
    Secondly i would check the fuse-able link marked 30b at the battery relay.
    Your machine will start and run normally but will not charge your batterys if that has failed
    With regards Davids machine I think you are not so lucky.
    In a conventional wired alternator if the light does not come on and the bulb and wiring is good it is usually the brushes worn out in your alternator, only minor repair.
    If it is like diagram above the cpu controls the light.
    Are all of your other functions in the cluster working correctly?
    is your machine charging? you need to provide all details.
    Cheers and good luck.
     
  18. David gladwyn

    David gladwyn New Member

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    Thanks for your reply been working on it today and think I have a few problems the bulb had gone in the cluster so fixed that. but still wont charge. And sometimes you need to tap the safety relay to get it to start. Could the safety relay effect the charging. If I were to excite the alternator which terminal would I use? Also one other thing that is a bit odd the automatic revving only works on the tracking not the boom?

    Thanks

    Dave
     
  19. 007

    007 Active Member

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    Hi Dave,
    I can explain in detail how that relay works if you wish but the short answer is possible but not likely.
    The only way it would interfere with the alternator is if the electronic side of that relay were damaged and shorting the sensing wire to ground.
    This would not allow the alternator to excite.
    The more likely cause of needing to tap it is there is large inrush of current on that relay which means the contacts need cleaning if you can get it apart without breaking it.
    Another possibility is a bad earth connection at that relay.
    Its actually a good ideal to try to excite your alt manually because it is also doing some very basic checks which will give you an idea how your alternator is.
    if you make up a couple of wires with a bulb holder to take a small 24V bulb like in the cluster 2-3watts.
    I can only go by the diagram unless you take a picture and post it.
    pull the plug with (small wires only) off the alternator and remove what is shown on the diagram as a link between B the output lug and the S terminal wire WB.
    Wire your bulb temporary between B the output terminal and the terminal shown as R where the LY wire was.
    Turn your ignition to the on position, the battery relay should be on and power from the battery should be present at the output terminal of the alternator.
    If the bulb is glowing this is good but if it is not you have probably got worn out brushes or your regulator is faulty.
    If the bulb is glowing start the engine and bring the revs up off idle and if the bulb has gone out you alternator has started.
    If the bulb is still glowing with the alternator running you have more serious issues in your alternator.
    If you have a multimeter i can step you through further tests.
    Cheers
     
  20. David gladwyn

    David gladwyn New Member

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    Thanks I've done as suggested and no joy. So have take the alternator apart cleaned the armature and hey presto it now charges and fixed the buzzer problem to. Thanks so much for your help. gonna start looking at the auto idle now today. It works on the tracking but not the main hydraulics? Every thing else works okay.

    Thanks Again

    Dave