Tips on Fujimoto CP-31 disassembly?
I bought a used CP-31 that is in mostly very good condition. Unfortunately, the recirculation pump for bath 3 doesn't work. It works for two seconds when you switch on the power, then it stops. And there is a leak from bath 3 that must be coming from the pump or one of the hoses connected to it.
Pumps for baths 1 and 2 seem to work fine, although the bath 2 pump isn't quite a strong as bath 1. The temperature controls appear to work for baths 2 and 3. I'm not sure about bath 1 yet.
I've removed the five screws that mate the black plastic molded bath section to the grey bottom section. I also removed the on/off switch. I can't get the parts to separate. Do I need to remove the eight screws from the two drive mount brackets also?
There are also screws in the bottom of the main unit. Do I need to remove any of those?
I don't want to break anything or disassemble more than necessary to get at the pump for bath 3. If anyone has ever done this and could offer some guidance, I'd appreciate it.
I've gone as far as taking the bottom off. Sounds like you took out the screws from the top side. Put them back, remove all the racks/rollers. Disconnect the plugs on the circuit board. Then flip the whole thing over. Take out the screws on the bottom and it should open up. There is a connector by the fan which you'll have to get as well.
The spray rods might need to be cleaned, I found a bit of debris in mine. The pumps do need to be primed - if your leak is letting air in before the pump it would stop it from pumping, best not to run it long this way. If I recall I had to reset the control board to get the first bath temp control to work.
It should look like this:
Last edited by George Nova Scotia; 08-06-2011 at 07:12 PM. Click to view previous post history.
George, thank you! Flipping it over and removing the bottom screws did the trick. It comes apart quite easily that way.
I found my leak, but there still seems to be something wrong with the pump for bath 3.
After I got the bottom separated from the top, I carefully flipped it back over and used some bricks and boards to raise the top black bath section up above the grey bottom shell a couple of inches. I filled all three baths. I used the priming funnels, as per the instructions to prevent air lock in the pump.
I saw my leak even before turning on the power. It's in the bath itself, not in one of the tubes. The step-down transformer in the lower right corner of your first and third picture has a white plastic part perpendicular to the windings. Each of the four corners of the plastic plate come to a curved point. The transformer twisted on its mount and one of those plastic points pressed into the end of the molded tank and put a hole through it. It was probably a casualty of shipping.
The number three pump comes on and circulates for anywhere from 2 to 20 seconds, and then it shuts off. There's a clicking sound, more like a clunk, when it shuts off. The agitation spray rod doesn't seem dirty or clogged. It sprays evenly and strongly across its entire width until the pump shuts off.
The pumps are magnetic drive pumps. What can go wrong with that kind of pump? Is there anything in blix or fixer (which is what would normally be in the 3rd bath for RA-4 or B&W processing) that could damage the impeller magnets?
By the way, the black bath unit looks like ABS plastic, but I am not sure. Can anyone suggest how to patch a small hole in it that will hold up to bleach or fixer?
If it is ABS then a small piece of ABS sheet glued with ABS plumbing glue should work well.
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I've only ever seen ABS plastic in pipe form at the local hardware stores, but I'm sure I can source some if it turns out to be ABS. I will call Omega-Satter or the joboman on Monday to see what they recommend.
I may take the mag pump apart and see if I can find a problem with it.
I would lay odds that if it is bath 3 there may be sulfation from old saturated blix building up in the llnes. Filp the thing (I wound my replenishment hoses up inside since I don't use them, and they are always in the way when flopped out.
ABS cement and shavings from a cut off black plumbing pipe may be a good fillier for your leak. Otherwise black RTV gasket maker for automotive uses can work well in these kind of situations.
The pumps are magnetic drive. If they don't spin well, the magnetic current just heats the stator of the motor. The motors are thermally protected to save against a melt down , and run off of 100V - that is what the transformer does - steps motor and controls down from 120v. The heaters are 120 powered though. I spent quite a while 'under the hood' of mine to figure some of this stuff out.
Remove the clips, and take the hoses off the tank and pump on tank 3. I think you will find a sulfur build up, or maybe even silver flakes if the blix was saturated. Something likel that , or a great deal of somethings like clumps of iron may also be attrached to the motor and 'magnetically shorting it out', or have plated onto the shaft.
I never could get my digital tank 1 thermostat to work. I replaced it with an analaog thermostat, and now run mine as tank 1 pre wet, tank 2 deve, tank 3 b/f and it works well this way. I have spare analog thermostats if it comes to that for you. I bought 5, when I needed one, because the price was right.
Watch out for dead tensioning springs on the racks. I replace mine with rubber drive belts of the sort you would replace in a cassette deck/8 track from an electronics wholesaler.
Get in touch if you ned more info.
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Thanks Mike. It'll be a couple of days before I have time to get back into it, but I'll follow your suggestions, starting with the pump.
This machine is incredibily clean inside and out, but I haven't looked inside any of the hoses. The person I bought it from said it was meticulously cleaned after each use. Absolutely no debris came out of the agitator bars when I tested it.
Pump 3 pushes water strongly and it comes out evenly through the agitator bar for the brief time that it operates (10 to 30 seconds) when I first switch on the unit. That suggests to me that the problem will be in the pump itself, and not a blockage or buildup of crud in the tubing.
I've found several aquarium stores that sell rebuild parts for the Iwaki MD-6 pump, including o-rings, impellers, front covers, bearing cups, etc. If the problem is in the pump, I suspect I will be able to rebuild it. If not, I'll contact Iwaki America and see if that pump is still available.
I haven't been able to find an MD-6 (actually MD-6-N) pump for sale anywhere. It may be discontinued. But the Iwaki MD-10 has the exact same dimensions, form factor, and bracket location as the MD-6 (looks like the same body, from the drawings on the Iwaki site), and it has the same hose connection types and sizes. It has a higher flow rate than the MD-6, so I'd have to restrict the flow on the output side to match the MD-6 if I end up having to completely replace the pump.
I have the W/D module and the replenisher for this unit too. I haven't checked out either of them yet.
I have the CP31 W/D as well.
I feed it and the main unit off a dedicated circuit breaker from the panel so as to not overload other circuits in the darkroom.
I use a GFCI repeptacle and put a bit of blue tack over the little green 'protection working' LED in it so as to not fog prints.
The thing takes it's signal from the main unit, via a non-standard din style plug. I think it has 3 pins.
It takes signals from the input sensors on the main unit to tell it when to fire up the i/r heater.
Mine started acting wierd a year ago, overheating. I replaced all the electrolyitic capacitors in the w/d board (watch out, one is bipolar), and it is back to behaving itself.
I never have figured out what the switch on it's board does; mine dries the print well in either position.
I have previously swapped capacitors in the main baord, and installed a new battery (I used a surplus handsfree phone rechargable battery).
The digital thermostat still did not work after this. That is when I fed the tank 1 a signal derived from an analog thermocouple reading off of the port where replenisher for tank 1 fed in. I stll have (somewhere) the notebooks (messy sketches) of the wiring if it helps.
I also have the operations manual from the old Jobo USA web site before it's demise.
There are good exploded view diagrams too I think I recall.
I can scan them and mail you a CD for the cost of a few bucks if you feel it will help you.
I fixed mine before finding this documentaion, so they are not really a must, but would be useful if trying to source an OEM part by part number.
The input sensors din plug is a wierd pin configuration as well. Mine has contact fingers broken in the main body female part so that only one sensor eye fires the unit out of standby. The print dryer still seems to work ok off of one yee, but the reprlesiher duty cycle signal would be screwed up if I used that option.
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