Jobo maximum liquid capacity

[Sal Santamaura]

I emailed Jobo about this weeks ago, but no response yet (other than an immediate "auto-reply" saying they got the question).

This page


http://www.jobo-usa.com/bulletins/b019.htm

indicates that recent CPA/CPP processors have the same rotation motor as ATLs. The instruction manual for ATLs specifies a maximum of 1.5 liter can be used in Expert Drums. Manual processor instructions limit chemistry to 1 liter in Expert Drums.

Since the CPA/CPP manual appears out of date with respect to rotation speeds (see this thread)


http://www.largeformatphotography.info/lfforum/topic/497510.html#506289

I wondered if it is also obsolete concerning ability to rotate larger quantities of chemistry. I asked Jobo whether it would be safe to use 1.5 liter with my post-22000 serial number CPA-2 and an Expert drum, or was there some limiting mechanical factor other than the stronger motor. I noted that I always "help" the lift by supporting most of the drum's weight from below when emptying it.

In the absence of a response from Jobo, has anyone with a newer CPA/CPP-2 used it this way, and have you experienced reliability impacts? Thanks in advance.

[Donald Hutton]

As seems to be the case too often, a phone call may be a much more effective way of communicating with Jobo. I have called them several times on various issues and found them to be excellent. Ask for Mark.

[Stan. Laurenson-Batten]

I am a user of the Jobo CPP2 with lift.

I have not had any problems with liquid capacity even with the large print tank for 24 x 20 inches.

It is wise to help the lift by taking some of the weight when lifting to empty.

I have had no difficulty in contacting JOBO, here in the UK or the US. In the early days I found their web site very useful.

[Oren Grad]

Sal -

I have a post-22000 (just!) CPA-2, but I wouldn't dream of using 1.5 L of solution in an Expert Drum. The 3005 in particular is so heavy as it is, and to my eye the motor seems to labor pretty hard to spin the thing even when I keep solutions down to less than 1 L. And the Lift arm feels like it will break off at any moment, even when I "help" with the drum.

Although I'm curious as to what Jobo will say, the CPA-2 feels to me as though it's just not built to take a beating. I think it's a fabulous tool and I'd hate to be without it, but I do feel I need to be careful with it.

[Tom Westbrook]

Ditto what Oren said. My CPP is serial number 24xxx and it sometimes seems to labor with 1 liter in the 3010 drum. It does seem to labor more if the upper tray water level is too high, though. It is curious that they claim the two motors are the same. I've never seen an ATL, but maybe it has lower friction components? Though it's hard to imagine that alone would compensate for a 50% increase in fluid volume.

Anyway, let us know what you hear from them. I use Xtol 1:3 with Tri-X, but as things stand now I can only process 5 sheets with 1 liter of dilute developer solution (I use a standard of 50ml stock per 4x5 sheet).

[Sal Santamaura]

OK, I just called Jobo's Customer Support number -- Mark answered. A significant difference between the ATLs and CPA/CPP is that Autolabs have dual drive gears, while manual processors include only one. Mark felt that even with the stronger motor, 1.5 liters of chemistry has the potential to put too much stress on the drive gear. He suggested measuring rotation speed with 1 liter of water in a drum, then adding 500ml to see how much it slowed down. He thought that more than a 10% drop might predict negative reliability impact.

For now I will stick with 1 liter maximum. When time becomes available, I'll try Mark's experiment and will also weigh both 3005 and 3006 drums to see whether the difference is comparable to 500 ml of chemistry. If so, using 1.5 liter in the smaller 3006 should be viable, although dynamic behavior of liquid could differ enough from a rigid mass of plastic to invalidate that conclusion.