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

[Greg Blank]

It does sound interesting, it's also encouraging that some people have this kind of knowledge to be able to think about and work out fixes and augementations to the processors. I support that! I have processors so anyone doing this stuff has my ear- beyond the job I do which is repairing and supplying Jobo information.

The only comment regarding the CPP2 I have is the the Motor control board for the CPP2 is a lot different than the CPE, in that other functions are present on the CPP2 board. the board has two circuits simultaneously present. On the right side of the board the motor controlling DC 24 volt circuit and the motor switch has a pot contained within the switch itself.

On the left the 110 Volt circuit which controls the heater, and pump which run off of 110V AC. The motor is easy enough to disconnect it just connects via two spade connectors located on the tranformer board. If the motor runs continously with a new contoller it may throw the existing reversal mechanism off, if that is included in the final modification.

There is also this interesting page:

http://tech-diy.com/jobo.htm

The suggestion is to replace the Jobo motor controller that alters the motor speed by voltage with a more modern controller that uses pulses of voltage at the full voltage (24v) to control the speed. The argument for this is that running large drums at low speeds with the original controller wears out the motor because the low speed means low voltage. Low voltage with the original controller means lack of torque due to reduced current. Using the pulse width modulation controller to slow down the motor while using the max amount of current (in pulses) does not suffer the same issue.

I'm going to test this theory out. I purchased a PWM-based motor controller board from eBay (24 VDC, supports reversal just like original controller, knob to alter speed with pot) for about $35 shipped from China. I've got a really early CPP-2 -- the serial number is in the 2000 range I believe and it is well used. I purchased a lift and the 3010 expert drum but after reading about all the potential problems, I decided to swap the motor controller before putting it to use.

The linked web page addresses this for the CPE-2. I'm assuming it is the same for the early CPP-2 and CPA-2 models. I haven't removed the circuit boards to get at the output of the transformer that should be converting 120 VAC to 24 VDC.

[Cymen]

I spent some time investigating the Jobo CPP-2 circuit. I was hoping one side of the big transformer output 24v DC but it looks like it outputs around 37v AC which is then converted by a somewhat complex circuit to variable DC to control the motor speed.

I'm no electronics whiz so I ordered a 110v AC to 24v DC 3A power supply. This way I can keep the new motor controller circuit completely separate from the original Jobo circuit (and easily revert to using the Jobo circuit). The power supply is going to take almost a month to get here so I'm going quiet for a while on this.

The parts I'm using:

Reversible 60W DC Motor Speed Control PWM Controller:
http://cgi.ebay.com/ws/eBayISAPI.dll...m=170401789775

24V 3A DC Universal Regulated Switching Power Supply:
http://cgi.ebay.com/ws/eBayISAPI.dll...m=260436605020

My plan is to hook this up to the incoming AC, the DC motor and the reversing switch (unplugged from Jobo circuit). Add a power switch and make a scale for the new knob that matches the RPMs of the original circuit.

I'll post one more update to this thread in a couple weeks with a link to another thread as I am going off topic of the original post.

[JR Steel]

I will just add I am processing my 4x5 in rollo pyro 500ml/10 sheets in my older CPP2 ser.# 14xxx. I read Gregs previous post about the unidirectional operation of the motor with the expert drums and modified my process to directional change once a minute during developer and one direction for all else in hopes of keeping it going. I have not noticed any change in results. I also read that use of rubber wheels on the carriage is recommended. Does anyone know where I can purchase some?

[Greg Blank]

They are easy running rollers, pretty certain we have them in stock at Omega.
We are currently doing our yearly inventory but will be back and running hopefully by Thursday you can call me at Omega our just shoot me an email there and I'll forward you details of price etc when I access my mail on Thursday.

gblank@omegasatter.com

I will just add I am processing my 4x5 in rollo pyro 500ml/10 sheets in my older CPP2 ser.# 14xxx. I read Gregs previous post about the unidirectional operation of the motor with the expert drums and modified my process to directional change once a minute during developer and one direction for all else in hopes of keeping it going. I have not noticed any change in results. I also read that use of rubber wheels on the carriage is recommended. Does anyone know where I can purchase some?

[John Powers]

They are easy running rollers, pretty certain we have them in stock at Omega.
We are currently doing our yearly inventory but will be back and running hopefully by Thursday you can call me at Omega our just shoot me an email there and I'll forward you details of price etc when I access my mail on Thursday.

gblank@omegasatter.com

Greg,

I believe these are #92167. At least this is what Ann Arbor sent me when they were still in business. Did you have a chance to check inventory and find a price?

Thank you,

John

[Greg Blank]

I know I have some. Not sure of that part will post you back with a price and details of ordering.

Greg,

I believe these are #92167. At least this is what Ann Arbor sent me when they were still in business. Did you have a chance to check inventory and find a price?

Thank you,

John

[Greg Blank]

Part number is correct, two of the rollers and support arms to a pack. Recommended retail around 42.00 US if bought directly from Omega. Omega as a distributor sets the MSRP (probably- based on some agreement from the original manufacturer) but does not encourage direct sales and therefore charges the full MSRP. I always try to encourage users to buy the parts from dealers that will willingly order them. Many dealers do not charge the full MSRP. Many users for sake of less hassle buy direct.

Using the part number JP92167 you can buy these direct from Omega at 800-777-6634 option four at the phone message, to speak with our customer service department.

Greg,

I believe these are #92167. At least this is what Ann Arbor sent me when they were still in business. Did you have a chance to check inventory and find a price?

Thank you,

John

[Dirk Rösler]

I processed for the first time with the easy running rollers yesterday and a 3005 Expert and the drum shook horribly while rotating. It seems that the rollers are not totally round in certain places. I went back to the normal rollers until I figure it out. Disappointing.

Also I did one directional processing this time and one sheet had an undeveloped/uncleared/unfixed area, so I am concerned about doing this again. I am pre-soaking etc. and never have issues with bi-directional rotation, in fact I went to bi-directional after having repeated problems on a unidirectional Unicolor base.

[mandoman7]

My understanding is that there is a bi-directional movement of developer over the film, even when the drum is rolling in one direction. As it rotates, the liquid is moving one way on the downward rotation, and then another way on the upward rotation.

When I switched to one direction I had no problems. The only unevenness I've had is when the drum is not level.

[Dirk Rösler]

I think the liquid still only moves in single direction in a tube. I have to add that this was with 500ml liquid and a fairly low speed setting, so I'll try with higher speed next time.