Jobo CPP2 wont reverse direction...

Discussion in 'Darkroom Equipment' started by PKM-25, Dec 18, 2012.

  1. PKM-25

    PKM-25 Member

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    OK, I am at my wits end here, did numerous searches and have come up with nothing, and I even remember seeing a post on this some time ago.

    I have inspected the inside of the main unit for moisture, made sure the relay that the "Chicken Foot" is attached to is working right, it all looks ok to me and I can only get one direction of of my Jobo CPP2 when operating. If you look at the gear from the end away from the main unit, the spin is counter-clockwise. I even move the claw around to try to re-engage it, I hear the click of the relay and then there is a slight hesitation and then it keeps going the same direction.

    Not really sure what to do here, as it works for one session one day, then the next batch it no longer reverses and today it never reversed.

    ????
     
  2. CatLABS

    CatLABS Subscriber

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    There are three components controlling the reverse. Either one of the three could cause the problem. In rare cases the microswitch has corrosion on it and will not engage the reverse contact, but that would be pretty obvious when looking at it.

    If you want to rule out motor malfunction, you can reverse the polarity of the motor, by unplugging it from the board, then reconnecting it the other way (black instead of green and green instead of black). If the motor now turns to the other direction it one of the above mentioned components.

    We can fix it for you if you want, or if you are handy with a solder i can try to help you DIY.
     
  3. amedway

    amedway Member

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    Are you sure that the mechanical part of the "chicken foot" behind the outer gear is working? From memory the switch on the back of the chicken foot triggers slight hesitation from the motor drive circuit and that's the moment that the big relay on the main board (I think) switched to reverse the DC to the drive motor. I can't remember where the drive for that relay comes from at the moment.

    I'm on hols at the moment, I'll have to search my workshop in a week or so when I get home to see if I still have my circuit notes from last time I repaired mine (different fault though)

    Hope this helps
     
  4. PKM-25

    PKM-25 Member

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    I will do the reverse polarity on the motor, if that is toast I might be OK because I have a spare. The microswitch is clean, I removed and inspected it last night and again today.

    Basically, I did a run of ten sheets last night, then 30 minutes later did two 120 runs in 2553 tanks and that is when it started acting up. I removed the head today, did a quick test and it reversed fine, then put it all back together, filled and warmed it up and bingo, it did it again, no reverse.

    I am on my third run of 4x5 now, have 5 more to do then I will start doing the above....I can solder, have two kits laying around...

    Thanks,

    Dan
     
  5. CatLABS

    CatLABS Subscriber

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    Sounds like a bad or oxidated reversing relay, as if you jiggled that around it did reverse for a while. We have a relay in stock, but before we send it out, you can test it with out taking the whole thing apart.

    You can remove the cover of the relay (clear plastic cover), dont worry if you crack it, you can replace it easily or glue it back on. See if you can manually actuate the relay and cause the motor to reverse. see if there is corrosion on the relay or inside the housing of the relay. If you have some contact spray\dielectric grease that can help.
    If after you recover the relay and try the machine again it still does not work - it might be one or more of the other components, or a bad\cold solder on the bottom of the main DC board, which happens over time, as the PC board degrades due to corrosion and oxidation.

    See if you can test the relay and report back.
     
    Last edited by a moderator: Dec 18, 2012
  6. PKM-25

    PKM-25 Member

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    Will do.

    Just for kicks I threw the chicken foot into the rotating gear while in a rinse and it did one reverse then it went back to it's old tricks again...
     
  7. PKM-25

    PKM-25 Member

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    I opened it up after running 80 sheets of 4x5. It did about half a run this morning and then quit reversing.
    So I did the reverse polarity on the motor leads, it worked fine. I then took the clear plastic cover off of the relay and tested it by hand, it reversed the motor no problem. I then took it all apart and inspected it all for any signs of corrosion, none, very clean as a matter of fact. I do not have any contact spray and would not be able to get any without ordering some since I am in a small town in the mountains.

    I checked everything several times over, took photos, etc. The problem still persists....
     
  8. Firestarter

    Firestarter Member

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    I have the exact same problem with my CPA2. Went through the usual checks as above and even replaced the relay with a new one but the problem is still there. So now I think the only other component in the chain that can cause the problem is the IC that controls the motor etc.

    Have not bothered going at it yet as I have been using a CPE2 for the past while until I build up the enthusiasm to order and replace the IC on the CPA2.

    Be interesting to see how you get on.
     
  9. PKM-25

    PKM-25 Member

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    Catlabs and I have isolated down to "maybe" it is a fried transistor.

    It's possible I am going to have to send the thing in and get it fixed...
     
  10. CatLABS

    CatLABS Subscriber

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    Dan - transistor on the way to you.
    Update us on how you progress.
    Good luck!
     
  11. PKM-25

    PKM-25 Member

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    Well I sent the brain of my CPP2 off to Catlabs to get fixed, got it back today after a reasonable turn around time and a very fair price. It works perfect, THANKS!!!!
     
  12. Sirius Glass

    Sirius Glass Subscriber

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    I am glad that your problem has been fixed.