I recently inherited what I believe is either a Jobo ATL-1 or 2 from my father and while it's mostly in working condition the chemical distribution arm on the back seems to be having some difficulty. I'm fairly comfortable with electronics so I started investigating and I think I have the issue narrowed down, but I'm hoping that someone with some knowledge about these machines can give me some pointers about the positioning of a few elements for reassembly and some debugging assistance in confirming my hunch.
The initial problem with the machine was that the cog that runs through the bottom and connects the air distributor switching wheel to the arm above had corroded and broken, which prevented the arm from moving. I replicated this part in CAD and replaced it with a 3D printed part and the arm started moving again. However, now the arm doesn't _stop_ moving, which I believe is related to the magnetic hall sensor on the underside of the head unit, positioned at the edge of the rotating air distributor wheel. I tried holding a neodymium magnet over the sensor to see if I could trigger it, but no dice. I then followed the wires to the plug on the front panel of the head and measured the voltages, but I got ~4.5V on on the yellow and green and -.7V on the white (measured against the power supply ground, so I'm guessing this is the regulated ground), which is confusing as the hall sensor is supposed to default to closed. I also tried (stupidly) to short what I thought was the signal wire to the current wire and blew a fuse. [edit] Update, I discovered that the version of the hall switch in the machine I have closes in magnetic field, rather than opening, and it appears to be working ok. So my next guess is that it's a problem on one of the boards. Any help in debugging what is going on here would be greatly appreciated.
The second issue I'm having is that the tension springs that help the distributor arm move correctly sprung while I was replacing the cog, and I failed to note what their correct position is. Any help on that front would also be appreciated.
The initial problem with the machine was that the cog that runs through the bottom and connects the air distributor switching wheel to the arm above had corroded and broken, which prevented the arm from moving. I replicated this part in CAD and replaced it with a 3D printed part and the arm started moving again. However, now the arm doesn't _stop_ moving, which I believe is related to the magnetic hall sensor on the underside of the head unit, positioned at the edge of the rotating air distributor wheel. I tried holding a neodymium magnet over the sensor to see if I could trigger it, but no dice. I then followed the wires to the plug on the front panel of the head and measured the voltages, but I got ~4.5V on on the yellow and green and -.7V on the white (measured against the power supply ground, so I'm guessing this is the regulated ground), which is confusing as the hall sensor is supposed to default to closed. I also tried (stupidly) to short what I thought was the signal wire to the current wire and blew a fuse. [edit] Update, I discovered that the version of the hall switch in the machine I have closes in magnetic field, rather than opening, and it appears to be working ok. So my next guess is that it's a problem on one of the boards. Any help in debugging what is going on here would be greatly appreciated.
The second issue I'm having is that the tension springs that help the distributor arm move correctly sprung while I was replacing the cog, and I failed to note what their correct position is. Any help on that front would also be appreciated.
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