Jobo ATL 1500 tanks stop rotating

<p>I'm hoping somebody might have a suggestion for what's proving to be a real problem with my ATL 1500. When processing conventionally loaded 2551/53 tanks, the drive mechanism sticks and stops rotating the tank at some point during development - which ruins the film. If I happen to notice it, a simple tap or nudge of the tank starts rotation again. Its been a problem for a while, and was filed mentally under 'known issues awaiting future investigation". Instead I normally just use the reliable smaller 2521 tanks, which have never produced this behaviour from the processor. Until yesterday that is! Again a nudge did free up the tank to rotate, but its hardly ideal.<br>

FYI I replaced the lift / drive mechanism on this machine a few years ago, and its had very light use since then, sadly. <br>

Searching around online has not produced relevant results, and I'm wondering if anybody here has dealt with this issue previously.</p>

<p>Thanks.</p>

<p>A CPE2 uses a relay to switch motor directions. The motor contacts burn after a while preventing good contact resulting low/no power to the motor.<br>

Jobo, like most other manufactures, use similar design and components from one model to another.<br>

Jobo use a DC motor for drum rotation. What you are experiencing is motor stall. Motor stall can be caused by worn drive gears which bind putting extra load on the motor. Such a bind should cause a motor hum when stalled or blow a fuse and can cause motor burn out (least likely). Worn brushes in the motor can cause the problem as well as a dirty commentator, the copper contacts on the motor the brushes make contact with (very likely). The motor is most likely a sealed unit meaning the motor was designed not to be disassembled but it can be done with care. The relay and motor power supply should also be suspect as the likely cause.<br>

The motor power supply will be a step down transformer converting 120V/220V to 18V - 24V AC. The secondary of the transformer is connected to a bridge rectifier and basic capacitor filter then to the relay or motor switching. Replacements for defective components should not be difficult to obtain from electronic supply stores if Jobo no longer supplies them.</p>

<p>Charles, that's a fantastic answer. I will follow up on this thesis when I get to the machine again, but it seems very plausible, and something I simply hadn't thought of before.<br>

Thank you.</p>

<p>The problem of your processor to be in electric motor, you'll need to remove it, open the electric motor, cleaning with a detergent dialectical, and replace the brushes, or easier to buy a new engine.<br>

Good luck</p>