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Thread: What happens to JOBO CPP2 processor with only 1st upgrade motor?

  1. #11
    Michael Alpert
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    Re: What happens to JOBO CPP2 processor with only 1st upgrade motor?

    Quote Originally Posted by Greg Blank View Post
    Bi directional rotation is required for paper processing and smaller film drums. For Expert drums it is not required, I've tested this myself in practice finding no difference in the results of developing sing PMK developer.

    I asked the question of the CEO of Jobo USA when the product distribution was being turned over to Omega Satter. His statement was that no, the Expert drums were not required to use it or for that matter designed to require it.

    After working on many many CPP2's over four years time, I am lead to believe that the bi directional motion weakens the motor circuit if one is using an Expert series drum, furthermore a overly filled Expert drum.

    What I do find required is the need to periodically lift the drum and insure that the chemical and water goes behind the sheets to wash off the anti halation backing. So I raise my drum once per minute for this purpose and turn the motor off while the drum is up and on once its back down.
    Greg,

    I've been uneasy about what you posted, so last night I looked in the Jobo manual and instruction sheets for more information. (I have yet to find a single instance where Jobo's manual is incorrect, though I am sure than one can use these machines in ways other than what Jobo envisioned.) In Jobo's instruction sheets for the Expert drums, it specifically says that the bidirectional switch should be turned on for normal use. I fail to see how the Expert drums would work differently than the smaller drums in terms of liquid flow. I think the idea behind the bidirectional rigmarole is to avoid streaks cause by unidirectional flow, similar to the need to slosh chemicals in different directions when tray processing. Also, the drums are made to use one liter or less; if someone uses more than a liter of liquid, they are asking for trouble. That is why, when using XTol for example, you need to limit how much you dilute a stock solution. If you dilute XTol more than 1*1, you risk not having enough actual developer within the one liter maximum. At the same time, there is a definite problem with the small motors in Jobo's processors. The company obviously was not able to fully retrofit the processors for the long-term power demands of Expert drums. Since the processors work terrifically well otherwise, we are all left with doing whatever we can to keep them operational.

  2. #12
    tgtaylor's Avatar
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    Re: What happens to JOBO CPP2 processor with only 1st upgrade motor?

    I may be wrong in this but I think it would be difficult to legitimately use more than 1 liter of chemistry in an expert drum. Xtol, for example and according to Kodak, requires 100ml of developer per 8x10 sheet which is equivalent to 4-4x5's. So for 10 sheets, you would need 250ml of developer. Diluted 1:3 that would add up to exactly 1 liter. I am not familiar with other developers whose dilutions would surpass the 1 liter mark.

    In my experience, C-41 requires the most chemistry - 330ml per 8x10 sheet according to Kodak. But 10 sheets in an expert drum would add up to 765ml of chemistry. On the other hand processing 120/220 rolls would quickly surpass the 1 liter limit using some of the Jobo drums.

  3. #13

    Re: What happens to JOBO CPP2 processor with only 1st upgrade motor?

    Quote Originally Posted by tgtaylor View Post
    I may be wrong in this but I think it would be difficult to legitimately use more than 1 liter of chemistry in an expert drum. Xtol, for example and according to Kodak, requires 100ml of developer per 8x10 sheet which is equivalent to 4-4x5's. So for 10 sheets, you would need 250ml of developer. Diluted 1:3 that would add up to exactly 1 liter. I am not familiar with other developers whose dilutions would surpass the 1 liter mark.

    In my experience, C-41 requires the most chemistry - 330ml per 8x10 sheet according to Kodak. But 10 sheets in an expert drum would add up to 765ml of chemistry. On the other hand processing 120/220 rolls would quickly surpass the 1 liter limit using some of the Jobo drums.
    Put five sheets of 8x10 in a 3005 and it's a different story. And the 3004/3005 drums are larger and heavier to begin with.

    I share Michael's view. And with bidirectional rotation, I've never had a problem clearing the antihalation dye in an Expert drum. Lifting the drum and turning the motor off and on every minute seems a fair bit of wear and tear in itself.

  4. #14

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    Re: What happens to JOBO CPP2 processor with only 1st upgrade motor?

    Quote Originally Posted by Greg Blank View Post
    I think only the ATL 2 plus and the ATL 3 because they were the only ones with 1.5 liter bottles. After those Jobo went back to a one liter bottle....but it could be other reasons that determined that.
    The limiting factor is a single CPA/CPP drive gear meshing with Expert drum lid cogs while the larger Autolabs use two.

    Quote Originally Posted by tgtaylor View Post
    I may be wrong in this but I think it would be difficult to legitimately use more than 1 liter of chemistry in an expert drum. Xtol, for example and according to Kodak, requires 100ml of developer per 8x10 sheet which is equivalent to 4-4x5's. So for 10 sheets, you would need 250ml of developer. Diluted 1:3 that would add up to exactly 1 liter. I am not familiar with other developers whose dilutions would surpass the 1 liter mark...
    Let's consider 8x10 film in a 3005 drum. Xtol, a very active developer, is relatively unique in its capacity of 80 square inches per 100ml of stock. So, if used at 1:3, that's (100ml +300ml) = 400ml of working solution per 8x10 sheet. Therefore, even with an Autolab, pushing the 1.5l limit to 1.6l, one would still be limited to 4 sheets of 8x10 and unable to put film in all 5 chambers in the drum. Other developers, many of which require 250ml or more of stock solution per 80 square inches, limit one to even fewer sheets of 8x10.

    This is why developers must ususally be used less diluted (or even undiluted) in the larger drums. Unfortunate, since more dilution is very beneficial to keep times reasonably long despite the continuous agitation and when trying to operate at higher temperatures.

  5. #15

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    Re: What happens to JOBO CPP2 processor with only 1st upgrade motor?

    How do you even defeat the bidirectional mode ?

    Is there a motor position or lever somewhere ?

  6. #16
    tgtaylor's Avatar
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    Re: What happens to JOBO CPP2 processor with only 1st upgrade motor?

    [QUOTE=tgtaylor;528792]I may be wrong in this but I think it would be difficult to legitimately use more than 1 liter of chemistry in an expert drum. QUOTE]

    Well, as pointed out above, I was wrong! In self defense I must admitt that as a 4x5 shooter I didn't think of 8x10 when I responded. In fact, I haven't even seen an 8x10 expert drum. But if you were using one you couldn't do more than 2 sheets at a 1:3 dilution.

    I wonder how much stock developers such as pyro and rodinal - which are diluted 1:50 or so - require? I was just on digitaltruth and freestyle's websites looking for developing times for Rollie 400IR (I have about a liter or so of Xtol remaining and was looking to see if it was doable at 1:1 as I do most of my B&W by hand inversion using Jobo 2500 tank which requires 1485ml of solution) and looked at the pyro and rodinal products but couldn't find any info on the amout of stock required to develope a sheet.

  7. #17

    Re: What happens to JOBO CPP2 processor with only 1st upgrade motor?

    Quote Originally Posted by Ron Bose View Post
    How do you even defeat the bidirectional mode ?

    Is there a motor position or lever somewhere ?
    I don't have the processor in front of me, but if I recall correctly, right by the coupler for the drum there's a little switch - a couple of plastic fingers - that gets tripped with each rotation, reversing the motor. You can flip it out of the way so that it doesn't get tripped. If somebody doesn't beat me to it I'll double check that next time I'm down in the darkroom.

  8. #18
    Greg Greg Blank's Avatar
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    Re: What happens to JOBO CPP2 processor with only 1st upgrade motor?

    That's fine, the beauty of the internet is everyone can be a critic and an expert and no one's wrong That is until almost everyone decides to gang up and say so. Nothing new about that, but I truely try,.. not to be know it all.

    I am only sharing my own experience and people can listen or not. I stated my suspicion concerning the bi directional stress on the internal circuitry, mainly because I frequently see the problem manifest in damaged processor components which are both electrical and mechanical. I also see lots of processors come to me that look like the user poured chemistry inside of them. So I was merely suggesting based on personal testing that I did. I encourage others to try in an attempt to have fewer problems to deal with as more and more people's processors age and the parts become no longer available.

    To let you know the Expert drums do in fact function much differently, one they are a hollow jacket that allows water to contact the inner tubes, thats what the small openings are on the bottom of the drum. Water flows in and out of the jacket. Which is why I say 1,000ml even for a 8x10 drum is far too much at once. Because that flowing water add weight your are not accounting for.

    To properly cover the 8x10 you might need 400 ml, tops....but to fully develop more.

    SO:

    I would split my developer and time into two steps, maybe three for more dilute dilutions. For instance PMK at 11 minutes, I do two changes each at 5.5 minutes and that also lessens the oxidization of the developer.

    Now for the interior of the drum: as the drum rotates the inner cylinders empty at the top and fill at the bottom. As they approach the top the developer streams parallel with the film and side to side producing a natural bi directional flow with without the drum reversing. Where as smaller drums don't pick up the fluid and the reels closely contact the film at the sprockets where unidirection will cause uneven results. The smaller drums always have fluid only in the bottom half so reversing is required.

    For what it's worth though I did find a note in the manual not to stop the motor when you raise the lift and lower the drum.....I just don't agree with the manual on that.


    Quote Originally Posted by Michael Alpert View Post
    Greg,

    I've been uneasy about what you posted, so last night I looked in the Jobo manual and instruction sheets for more information. (I have yet to find a single instance where Jobo's manual is incorrect, though I am sure than one can use these machines in ways other than what Jobo envisioned.) In Jobo's instruction sheets for the Expert drums, it specifically says that the bidirectional switch should be turned on for normal use. I fail to see how the Expert drums would work differently than the smaller drums in terms of liquid flow. I think the idea behind the bidirectional rigmarole is to avoid streaks cause by unidirectional flow, similar to the need to slosh chemicals in different directions when tray processing. Also, the drums are made to use one liter or less; if someone uses more than a liter of liquid, they are asking for trouble. That is why, when using XTol for example, you need to limit how much you dilute a stock solution. If you dilute XTol more than 1*1, you risk not having enough actual developer within the one liter maximum. At the same time, there is a definite problem with the small motors in Jobo's processors. The company obviously was not able to fully retrofit the processors for the long-term power demands of Expert drums. Since the processors work terrifically well otherwise, we are all left with doing whatever we can to keep them operational.

  9. #19
    Greg Greg Blank's Avatar
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    Re: What happens to JOBO CPP2 processor with only 1st upgrade motor?

    A little more to it than that I think. But it is a valid point, the ATL's also in addition to the motor that turns the drum use a second motor to raise the arm. The motor that raises the arm has a brass gear that is set on a much heavier weight spindle than the cog that screws into to the CPP2/CPA. The motor that drives the drum on the ATL utilizes a magnetic sensor that controls the voltage ramp at the precise decided spot where the drum is to reverse when the polarity is signaled to change. The CPP2/CPA utilize a a small mechanical micro switch that connects to the three fingered gear....so it hits and the voltage changes polarity all at one time. Evenually the mechanical relays and or switches wear out.

    FWIW no one I have ever talked with uses more than 1,000 of chemistry. Even John Sexton stated in his Jobo Quarterly article that he uses 850ml for 8x10.

    [QUOTE=Sal Santamaura;528819]The limiting factor is a single CPA/CPP drive gear meshing with Expert drum lid cogs while the larger Autolabs use two.

  10. #20
    Greg Greg Blank's Avatar
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    Re: What happens to JOBO CPP2 processor with only 1st upgrade motor?

    Hi Oren;

    There are two ways to look at that I guess, I use less chemistry so tipping the drum may be needed versus using 1,000 ml to remove the anti halation coating.

    As for producing more wear...well I know I can get the Motor rotation switch right now and it cost about 55.00 dollars. Even someone with not alot of knowledge could solder it on the circuit board if they knew the switch was the only bad problem.

    That switch only regulates the voltage ramp to the motor and turns the motor on/off.
    Usually the switch becomes loose or too tight when it fails....and the motor stops of course

    If the motor reverses there are at least two components that a heavy drum might damage. The two of the components are on the bottom transformer board and currently cost about 100 for the parts plus three hours for me to disconnect, resolder and test the processor for return to a given customer. I am sure you can do the math at $100.00 per hour.


    Quote Originally Posted by Oren Grad View Post
    Put five sheets of 8x10 in a 3005 and it's a different story. And the 3004/3005 drums are larger and heavier to begin with.

    I share Michael's view. And with bidirectional rotation, I've never had a problem clearing the antihalation dye in an Expert drum. Lifting the drum and turning the motor off and on every minute seems a fair bit of wear and tear in itself.

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