UMO runaway

[peggyb 169]

My 4 years old UMO is having trouble lately, after performing really nice over the past years (same quality as UM2)

This time only 25 minutes into a print it goes off.... The printhead leaves the print in the X and/or Y direction (random) and comes back to and resumes the print. Even the material feeder gets involved, it spins back and forth, and resumes...

So every motor, except the Z, gets crazy..... What is this???

This happens almost every time now, sometimes a print finishes perfect (all same gcode), sometimes it starts after a few hours. I can touch the motors by hand, they are hot, but not untouchable, underneath at the electronics board there is nothing hot, I put the UMO on empty spools to lift it from the table. Once I triggered the runaway printhead by pushing the controller button. A sign that things are off can be seen in the controller: if I wanted to start a new print, the screen stays empty only showing 'main:' or not being able to reach the 'print from sd' menu.

 

[valcrow 144]

Those are some strange symptoms... Is your motherboard fan OK? the older UMO's have some notoriously bad mobo fans, and the lack of cooling on the stepper drivers make it do some crazy things that I would not have thought possible.

On a side note, this is the cleanest 4yr old UMO I've ever seen. Mine was more mess by the first week.

[peggyb 169]

yes, the fan is running underneath, did have this problem a year ago... but then it does not return to to right position, it just prints shifted.

just started a new print, same issue, triggered it after I wanted to decrease the speed by turning the controller. Even the bed/z drops now (at 0.41)

 

[peggyb 169]

any ideas?

is this the board? It is strange that all motors/steppers are involved, so it must be something different. Or is the ulticontroller to blame, or cables, or.......?

Would this mean a new electronics board? (expensive) this one is still a 1.5.4 version, and if so, can they be swapped easily without special 'somethings'.....

[ultiarjan 1,208]

I don't have any idea about the cause to be honest, but did you check the obvious, different G-code, different SD card?

Do you know anybody close by with an UMO? Just swapping components 1 by 1 will eliminate causes.. I guess swapping and testing if its the ulticontroller is the first and easy thing I would try.

[peggyb 169]

I have 2 UMO's, so swapping is a good idea. It is not the gcode/sd card, because the print finished fine on the other UMO.