Omnistep with single poll switch

Discussion in 'Tech/Mech General' started by marksmith, Sep 11, 2013.

  1. marksmith

    marksmith Read Only Funster

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    Hi folks,

    The electric step on our motorhome has failed. It went through some weird interim behaviours involving long beeps and retracting itself without being asked, but now it just doesn't work. Stuck in the retracted position. Press the button and it beeps but does nothing.

    It's marked "Omnistep" and a Google search for that gives wiring diagrams but they are not for the right model. This one has a single button (SPST) which both extends and retracts the step. Connected to the button are only two wires.

    The step also automatically retracted when the engine was started.

    The rest of the wiring is inaccessible under the stove (helpful!) so I can't see what we've got.

    Any hints or tips please? A wiring diagram would be useful.

    Thanks!
    -Mark
     
  2. andeb

    andeb Read Only Funster

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    Mark,

    We had a similar problem with a TAG EUramobil that we owned. Despite spending hours trying to rectify the problem, no joy!!

    Eventually we found that the leisure batteries were discharged and this was causing the problem. Once recharged the problem went away.
     
  3. marksmith

    marksmith Read Only Funster

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    Thanks andeb. Unfortunately that's not the problem in this case - both batteries fully charged.
     
  4. jhorsf

    jhorsf Read Only Funster

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    When I had a problem with the awning Peter JCM sent me here as I was only 6 miles away at the time they are the importers for the UK a young man sorted my problem out while I waited they are the experts .I would say give them a ring they are very helpful and will probably know what is required and stock all the parts

    Rose Awnings
    sales@roseawnings.co.uk
    Unit 10, 565 Blandford Road,
    Poole
    Dorset
    United Kingdom
    BH16 5BW
    Phone no. 01202 620427
     
  5. estcres

    estcres Read Only Funster

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    I experienced a similar problem several years ago, except that it would not return on engine strat up, I tried quite a few ways to repair it and ended up hitting it with a hammer in frustration and it started working correctly.

    Someone mentioned later that the changeover relay can get stuck in one position and does not operate properly.
     
  6. dave newell lvs

    dave newell lvs Trader-Vehicle Services

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    Having seen several of these steps fitted to various CI brand motorhomes I'd say its one of two things. Either the mechanism has become dirty/rusty and stiff or the control unit is up the swanney. Try giving all the hinge joints a good dowsing with penetrating oil first and then working the mechanism back and forth to start with.

    D.
     
  7. mitzimad

    mitzimad Funster

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    theres a micro switch that determins the step position and changes direction its usually this thats full of gunk
     
  8. Rob e Lee

    Rob e Lee Funster

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    That's what happened to mine - just squirted lots of Penetrating Oil, been ok since.

    Rob
     
  9. marksmith

    marksmith Read Only Funster

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    Thanks for all the replies. Dave Newell was the closest - the step itself is fine and extends and retracts if you put power on the wires, but the controller has blown up - almost literally.

    Found the controller (quite a job in itself) and took it apart - it's an unbelievably high-tech controller for such a simple job. There's a little FET which looks like it switches output on/off. It's gone open circuit and melted - blown itself off the circuit board.

    Contacted a RollerTeam dealer and the controller is £130! It's called an ES703 (replacement is ES803). Anyone heard of it?

    I reckon I can replace the controller with a simple relay if I change the switch too, and add a bit of wiring... but if anyone knows of a better way, I'm all ears.

    Thanks!
    -Mark
     
  10. bailey

    bailey

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    By a step
     
  11. TheBig1

    TheBig1 Funster Life Member

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    with considerable rewiring, you could certainly use relays to do the job of the control board. to make it simple, use a cheap central locking controller to do the switching.

    what has probably happened to the original is that the hinges are getting stiff putting more load on the motor and controller causing it to blow. thoroughly service the step hinges and mechanism and keep it clean and greased to avoid it happening again
     
  12. marksmith

    marksmith Read Only Funster

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    ;-)

    I don't think there's any need for a central locking controller. Just a crossover switch (like most steps use) and a DPDT relay (or two SPDT relays, probably). The step already has a switch which breaks when the step is retracted - use that to switch off the automatic retract.

    That's a good suggestion, thanks. It moves very quietly and smoothly, and inside the step it was all pretty clean. But I'll get it off again and clean and grease the mechanisms just to be sure. It is a bit of a mystery why the controller blew up. The offending smoldering FET was rated for 28A continuous (!) and I measured the motor's stall current at just under 10A... but perhaps the rest of the circuit board melted first.
     
  13. cbr786

    cbr786 Read Only Funster

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    I know its is a old post but I think information might be useful to other people in similar predicament.
    I own a fiat Ci 2004 MH my steps one night started to act crazy opening and closing by them selves. I pulled the 10A fuse in the shunt unit to stop this activity.
    On removing the dometic fridge cover the lower one I saw the relay box ES703 I unplugged the 3 bunch connectors going to it and opened up this plastic box to find a PCB with a burnt FET transistor.

    The part number was still readable although it had nearly melted it read LR2705.
    this part is £0.50 from an electronics retailer and if you are not happy doing the soldering and good electronics repair shop should clean your board and solder the chip on for you.

    I am yet to do this this on my own MH will update my findings. On another issue my linear actuator broke its plastic mounting head as well so I had to mount it with an extra long 6" threaded bolt and jubilee clips on the main housing to hold the actuator in place.

    that works for now but for how long I have no idea lol.

    This is a good forum and i look forward to reading some of the threads and trying to contribute at the same time. :Smile:
     
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  14. Dawn B

    Dawn B Funster

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    There's a lot to be said for manually operated bits and bobs. Seems life is easier with the older models :Wink:
     
  15. marksmith

    marksmith Read Only Funster

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    That's exactly what I found too but unfortunately the board under the FET, including the tracks, was badly scorched so I don't think repair is going to be possible.

    I'm going to rewire it with a two-way switch at some point, but we've stopped using that door now anyway so it's not urgent :)

    Thanks for the reply!
     
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