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  1. #1
    Gatsby1923's Avatar
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    A Jobo Issue- A Stalling Motor.

    Here is another Jobo question. The motor on my CPE-2 Stalls. If it is under no load it seems OK. I put on a film tank it will stay fine for the first 3 or 4 minutes, then slow down and stall. I'll turn off the motor for a few minutes, turn it back on and it will run fine again for 2 or 3 minutes then stall. I am using the correct tank rollers and not over filling the tank. The stalling seems to be interdependent of when the machine reverses. Before I go tearing the thing apart what am I looking for? Do you think some 3 in 1 oil is all it needs, or is this a major issue? I do know the machine was sitting for many years before I became it's new owner.

    Dave M
    I don't know where I'm going, but I'm on my way.
    Carl Sandburg

  2. #2
    Sirius Glass's Avatar
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    A wild guess, but it sounds like a resistor failed and a capacitor is charging up completely. Since the capacitor does not discharge, the motor stalls.
    Warning!! Handling a Hasselblad can be harmful to your financial well being!

    Nothing beats a great piece of glass!

    I leave the digital work for the urologists and proctologists.

  3. #3
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    The motor probably needs cleaning out, it'll be full of dust caked into dried-up grease and the like. Degrease it all, make sure the brushes are in good condition and carefully place a drop of machine oil ONLY in the shaft bearings. Perhaps some grease on gears, that is all. Your stalling is probably temperature-induced due to the motor being overloaded by the gunk in it. Try running it with the case off and see if the motor and/or control electronics gets hot; my guess is that they both do.

    Mine (well, a CPP-2) has a similar problem with the pump - it required disassembly and cleaning after being stored for a couple of years because it was completely seized.

    Sirius, with all due respect, bollocks This is not the snubber-network failure. There is nothing like you describe in the DC circuitry that drives the motor.

  4. #4
    Sirius Glass's Avatar
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    polyglot, I used the words wild guess. I was a shot in the dark. Lighten up. Watch the bollocks, you seem to be stepping into it.
    Warning!! Handling a Hasselblad can be harmful to your financial well being!

    Nothing beats a great piece of glass!

    I leave the digital work for the urologists and proctologists.

  5. #5
    polyglot's Avatar
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    Quote Originally Posted by Sirius Glass View Post
    polyglot, I used the words wild guess. I was a shot in the dark. Lighten up. Watch the bollocks, you seem to be stepping into it.
    Smiley face placed in prior post for positive effect...

  6. #6
    Photo Engineer's Avatar
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    Jobo suggests regular lubrication to prevent this type of problem. There was even a report of the type of lubricant needed to be best for this motor and drive shaft.

    I believe it was in the Journal of Rotary Processing published by Jobo.

    PE

  7. #7
    Gatsby1923's Avatar
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    Thanks, I pulled the thing apart. Let's just say the engineering in the machine is very "Germanic." I pulled out the motor which is fully sealed and dropped some 3in1 around where the shaft goes through the transmission, hoping to get some to seep in... No Dice... I did see a large hole in the top of the motor but I don't think there are any bearings in there. Well I am done for the night. I'll play with it more tomorrow.
    I don't know where I'm going, but I'm on my way.
    Carl Sandburg

  8. #8
    Sirius Glass's Avatar
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    Does it come to a stop when the "claw" switch is about to change the direction?
    Warning!! Handling a Hasselblad can be harmful to your financial well being!

    Nothing beats a great piece of glass!

    I leave the digital work for the urologists and proctologists.

  9. #9
    Gatsby1923's Avatar
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    Click image for larger version. 

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    That's what the inards of the machine look like. There is no "claw" but when it stalls it makes that motor is stuck hum. It also happens indipendant of the machine reversing.
    I don't know where I'm going, but I'm on my way.
    Carl Sandburg

  10. #10
    polyglot's Avatar
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    Quote Originally Posted by Gatsby1923 View Post
    Click image for larger version. 

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    That's what the inards of the machine look like. There is no "claw" but when it stalls it makes that motor is stuck hum. It also happens indipendant of the machine reversing.
    That hum you hear is the transformer being overloaded because the stalled motor is pulling loads of current. The slower a motor goes, the more current it draws; at stall, the current is limited only by the (very small) series resistance of the windings and the series resistance in the transformer. Leaving it powered like that will make things very hot and you stand a good chance of blowing something.

    The fact that it hums like that means that the controller is successfully applying power to the motor; your fault is almost-certainly not electrical unless it's a short inside the motor. You're going to have to replace or disassemble & repair the motor, sorry. My money is on gunk in the worm-drive gearbox that you can see on the end of the motor.

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