Jobo ATL-2 rebuilding project

Kino · Sep 3, 2025

Kino said:
Random bit of information: This is a direct replacement for the water circulating pump on an ALT 2200/2300:

BOSCH 0392020024 Original Equipment Electric Auxiliary Engine Water Pump - Compatible with Select Volkswagen Beetle, Golf, Passat

This can still be found in auto parts dealer inventories for now and currently runs about $60 USD.

Oh and BTW, this part is now $90 to $250 in the USA when you can find it...

MicheleRubino · Sep 3, 2025

You mean doing the bleach-fix outside the machine? Why this? Even if every use I do a cleaning cycle?
Ps the water pump is quite cheap in Italy/europe, about 26/30€ in some places

Kino · Sep 3, 2025

MicheleRubino said:
Ps the water pump is quite cheap in Italy/europe, about 26/30€ in some places

Not a surprise for obvious reasons.

MicheleRubino · Sep 14, 2025

How much complicate is to unmount the jobo atl2 for a good clean and maybe how difficult is changing the silicone chem pipes? thanks in advance

Kino · Sep 14, 2025

MicheleRubino said:
How much complicate is to unmount the jobo atl2 for a good clean and maybe how difficult is changing the silicone chem pipes? thanks in advance

My chem pipes are sealed-in with silicone and are hard to trace without taking the head apart. I refused to dismantle the head unless it is absolutely necessary.

To clean these pipes, I attached a bit of microfiber cloth to the end of a moderately flexible bit of insulated copper wire and pushed it up into the discharge port of each chemical bottle. I then poured a citric acid mixture down to fill the tube and let it soak before flushing with several liters of water.

You can even swab the length of the pipe with the microfiber contraption IF you don't get too aggressive and are patient.

Seems to have done the job and cleared the tubes.

mshchem · Sep 14, 2025

Citric acid is great for lime. Slightly warm the solution too.

I worked in an analytical chemistry laboratory for several years we used formic acid to clean steam generators. Nasty stuff and expensive, worked great.

Bar keeper's friend works well too.

MicheleRubino · Oct 14, 2025

Hi everyone, so they give me this atl2 and from the videos they sent before picking it up machine was turning on good. Now I started cleaning it and wanted to reset some programs… now the machine gives me 30.00 error with 3 blinking. I can check the temperature, moving the arm but nothing else.
Any suggestions?
Thanks
Michael

adamlugi · Nov 3, 2025

Hello, I would like to kindly ask for your advice.

I need to repair the SET/RUN rotary switch in my JOBO ATL-2 Plus, but I am not a technician and have very limited experience with electronics.

Could you please guide me on how to properly access and replace this switch?

Do I need to remove the front panel first, or is the knob separable from the outside?

Any detailed instructions or tips would be extremely helpful.

Thank you very much in advance.

christophern · Dec 19, 2025

Fred of Wisconsin said:
I am in the process of rebuilding a Jobo ATL-2 that I stubbornly purchased from someone who should NEVER be allowed to own any photo lab related equipment. This rebuild is truly a project but my intentions are to hopefully persevere.

I owned several ATL-2s through the years and I have a soft sport for them in the lab. I only wish Jobo was still producing these Auto Labs as new and parts would not be a monumental search or a price gouge when the part is found. I have had some luck with finding parts though and my background helps with the tearing down and now the reassembly. I have had to replace several discreet components and repair cut circuit traces but I now have a some life in the unit. Some important tests are ahead before I run a test roll of film.

I am always on the hunt for any ATL-2 machines and components that may still be out there.

Fred.

Hello Fred,
This thread is more than 5 years old, so I don't know if you get this ...
I'm in Europe .. I own an 'ATL-2 Plus' (which I'm sale here -- sorry, not to the U.S. ... anyone in Paris is welcome to contact me, though!) and an ATL-3, which I'll keep. I've never actually activated either of them and — to make sure I don't become like the guy who you said "should NEVER be allowed to own any photo lab related equipment", I like to keep direct contact with people like yourself who have experience and advice about the particular equipment. If you're still actively using your machine and OK with the idea, I'd really appreciate if you contacted me by DM!
Best,
Christopher

Bjornaagedk · Dec 26, 2025

Hi!

I just came across this thread.

I have a Jobo ATL-2 Plus that has been unused for more than 15 years. I’ve tried starting it up, and both the pump and the heating element are working fine. I was able to run a complete processing cycle using water in the chemical containers.

But then problems appeared!
Suddenly the waste arm started moving heavily, and you can hear that the motor sounds strained.
At position 1, the machine now reports “Error 3”.

According to ChatGPT, this has something to do with the air distributor.
I disassembled the machine (following steps from chat gpt) without touching the air distributor, and I carefully removed and cleaned the waste arm.
It has now been reinstalled, but the machine still reports Error 3 on startup.

ChatGPT says that Error 3 can also be caused by the waste arm not being positioned correctly in relation to the zero-position sensor.
Additionally, I have discovered that a thin white wire going from the front part to the motor has come loose.
Could this also cause Error 3?

I am knowledgeable in electronics and have approached this very methodically, but I have never disassembled an ATL before—it’s quite a complex machine.

Is there anyone here who can help me moving further?
Is it possible to remove the entire air distributor with the motor and resolder the white wire?

When the machine is started, it immediately reports Error 3, and the waste arm moves a bit forward, then a bit back, and ends up positioned halfway over drain outlet 1.

Any good advice on what the next step should be?

Best regards
Bjorn

Fred of Wisconsin · Dec 26, 2025

Bjornaagedk said:
Hi!

I just came across this thread.

I have a Jobo ATL-2 Plus that has been unused for more than 15 years. I’ve tried starting it up, and both the pump and the heating element are working fine. I was able to run a complete processing cycle using water in the chemical containers.

But then problems appeared!
Suddenly the waste arm started moving heavily, and you can hear that the motor sounds strained.
At position 1, the machine now reports “Error 3”.

According to ChatGPT, this has something to do with the air distributor.
I disassembled the machine (following steps from chat gpt) without touching the air distributor, and I carefully removed and cleaned the waste arm.
It has now been reinstalled, but the machine still reports Error 3 on startup.

ChatGPT says that Error 3 can also be caused by the waste arm not being positioned correctly in relation to the zero-position sensor.
Additionally, I have discovered that a thin white wire going from the front part to the motor has come loose.
Could this also cause Error 3?

I am knowledgeable in electronics and have approached this very methodically, but I have never disassembled an ATL before—it’s quite a complex machine.

Is there anyone here who can help me moving further?
Is it possible to remove the entire air distributor with the motor and resolder the white wire?

When the machine is started, it immediately reports Error 3, and the waste arm moves a bit forward, then a bit back, and ends up positioned halfway over drain outlet 1.

Any good advice on what the next step should be?

Best regards
Bjorn

Fred of Wisconsin · Dec 26, 2025

Hello.. Without having the board on the bench, in the past and with prior experiences the #3 error code you are asking about was often caused on the 94017 Interface Board Control Head and not the manifold system. This board is responsible for all the motor and valve functions in the head. In past failures this part has been the culprit and it is a 1µF tantalum capacitor at location C7. Hope this helps.

Bjornaagedk · Dec 28, 2025

Hello Fred.
Thank you for your reply.
Do you have a pdf copy of the service manual for ATL2 plus? Or do you have a link to this?

Bjornaagedk · Jan 1, 2026

138S said:
I'm rebuilding an ATL 2500+

I'm making a totally new electronics for it (Arduino Mega + ESP-32 web interface),

Attached (bottom) there is the state machine pdf design that will control it. https://www.photrio.com/forum/attac...5/?temp_hash=50a07aa8b7633f2d8b11a4e024acd3d9

I supress the pneumatic distributor with the malta cross by using an array of six air valves. Bye bye distributor

I'm to control the output nozzle with a servo. I replace all plastic tubes by silicone tubes, I place a pressure sensor just after the air pump to check pressurization in the active bottle, this would diagnose pressurization an lack of liquid. I also place a flow meter for the rinse water.

All materials are cheap and reliable, Arduino/Marlin/Prusa style.

By now I understand well all sensors and actuators. Now I'm making a "test bed" to make the process manually with switches to "feel the machine" later I'll implement the control in the Mega/ESP-32 and finally I'll make a decent electric cabinet for it. I'm to place the air pump and the valves in the cabinet, so the all control will be outside of the machine for easy service.

Goal is to have a reliable machine that has to be very easy to service.

I know absolutely nothing about the original electronics, I stripped it the very first day, but I know quite well all sensors and actuators it has, if you have any question.

This is the "test bed" for the electronics:

View attachment 237317

A disassembled ATL 2 is a quite scaring thing !

View attachment 237318

This is the reason because that machine was retired, a hidden broken sprocket that failed intermitently...

View attachment 237320

Just came across this 6 year old post.
Did you manage to build a new "air distribution unit" with Arduino?
Any pictures, or descriptions on how this can be done?

BR
Bjorn

Fred of Wisconsin · Jan 1, 2026

Hello Bjorn... sorry but I did not manage to build an air distribution unit. I have always been able to scavenge parts that were needed. Unfortunately with the processors becoming much more scarce finding some of the parts is starting to become impossible.

Bjornaagedk · 2026-02-05T11:20:11-0500

Is the spring installed correctly? I think it is very tight. ???

Bjorn

Fred of Wisconsin · 2026-02-05T16:22:46-0500

Hello.. yes it is installed correctly. It is designed to move the arm from location to location with the ability to swing independently if necessary. The spring will sit with the white tab on the gear between the springs prongs.

Jobo ATL-2 rebuilding project

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