JOBO CPE-2 modification questions

[aaronsd]

Hello-

I have a JOBO CPE-2 that has been modified with an extra AC plug and light/button. I think this machine was adapted for E-6 processing but I'm not sure and I'd appreciate any information or advice before I start to revive the machine for use with B/W chemistry.

Thank you.

best,

Aaron

[Duolab123]

Hello-

I have a JOBO CPE-2 that has been modified with an extra AC plug and light/button. I think this machine was adapted for E-6 processing but I'm not sure and I'd appreciate any information or advice before I start to revive the machine for use with B/W chemistry.

Thank you.

best,

Aaron

Looks like someone wanted to use a enlarger timer to turn off the motor when step was complete??? Hard to guess what exactly was setup. Did the timer act as a switch or did it supply power? Maybe fill it with water to check heater first. Next, I would try shorting the "timer plug to see if it was hot, this would be unorthodox.

My bet is a enlarger or Gralab timer supplies power to the motor. It's kinda cool setup. ��

[Greg]

Many years ago I also acquired a used CPE-2 (90% sure on the model) that had an additional AC cord (with ground), an added light, and an added rocker switch. The modification was very well done and could have easily been mistaken to be a factory mod. Couldn't figure out what the modification did until I took the JOBO apart. Inside the AC cord, rocker switch, and light were never wired or connected to anything or even to each other. Back then never figured out what the mod was made to do.

Currently have and use a CPA-2 with a Lift. Does anyone know where wiring schematics for JOBO processors can be found? Would sure be of help to aaronsd and myself.

[Duolab123]

Hello-

I have a JOBO CPE-2 that has been modified with an extra AC plug and light/button. I think this machine was adapted for E-6 processing but I'm not sure and I'd appreciate any information or advice before I start to revive the machine for use with B/W chemistry.

Thank you.

best,

Aaron

Did you figure this out? If a timer controls the motor that's kinda neat!

[Joshua Dunn]

Back in the day Jobo had a factory approved modification where the heating element and the rest of the unit (the control board and motor) were powered separately. You could plug the heating element into the wall for power and the rest of the unit into a backup power supply. Batteries weren't very good back then, the idea was if the power went out, the heating element (which draws the most power) would lose power but the rotating motor and circuit board (which draws much less power) would not. That way the development could finish in the event of a power outage.

-Joshua

[aaronsd]

Success! Thanks for the ideas and interest.

I decided to plug the JOBO into a Gralab 451 timer yesterday and it all seems to work. The timer controls the motor rotation and I now have an audible beep at the end of each cycle. The "LIGHT OFF-UP" label and red button confused me for a minute until I realized it was to turn off the heater light to prevent film fogging. I checked to make sure the heater still works while the light is off. The modification was done very cleanly so I'm assuming it was likely a professional modification by someone providing this service at the time? It would seem to tighten up process control as I think the machine was previously used for E-6.

The battery backup idea is intriguing!

I'm curious what do people see as the advantage to this precise timer/motor control?

Thanks again.

best,

Aaron

[Duolab123]

Success! Thanks for the ideas and interest.

I decided to plug the JOBO into a Gralab 451 timer yesterday and it all seems to work. The timer controls the motor rotation and I now have an audible beep at the end of each cycle. The "LIGHT OFF-UP" label and red button confused me for a minute until I realized it was to turn off the heater light to prevent film fogging. I checked to make sure the heater still works while the light is off. The modification was done very cleanly so I'm assuming it was likely a professional modification by someone providing this service at the time? It would seem to tighten up process control as I think the machine was previously used for E-6.

The battery backup idea is intriguing!

I'm curious what do people see as the advantage to this precise timer/motor control?

Thanks again.

best,

Aaron

You can work around the darkroom on multi-tasking, if this is hooked up to a Gralab 300 old fashioned timer the buzzer would sound and call you to attend the machine

[aaronsd]

You can work around the darkroom on multi-tasking, if this is hooked up to a Gralab 300 old fashioned timer the buzzer would sound and call you to attend the machine

You're right the Gralab 300 is a much better match than the Gralab 451 I used. I realized the 451 is a bit of a hassle (or worse) when used for this application because it is meant for enlarging where relatively short times are being used. I don't have access to my Gralab 300 right now so I'll need to continue to improvise but I'm happy it's working and one roll of 120 and one 35mm were successfully processed the other day. The heating thermistor/temperature circuit is possibly broken as the temperature seemed to keep rising.........

Thanks for the help and suggestions!