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First, my Rostock Max v2 was printing perfectly fine when I noticed a fan power cable had come unsoldered.

I mistakenly thought I could quickly solder the cable right back to the fan, but I accidentally touched the fan +/- cables with the soldering iron and thought I ruined my Rambo board as it immediately shut off and would not power on.

I bought a new fuse and replaced it and it started working (or so I thought). I also switched to PETG at this same time.

The PETG printed terribly with the printer crashing into the print at various heights, so I swapped back to PLA.

Around the time I swapped to PLA, I recalibrated the printer endstops with an Indicator Dial attached to the effector (everything was calibrated perfect).

I also checked and retensioned all the belts.

I've also rewritten the Repetier and cleared and rewritten the EEPROM.

I reconfigured a Raspberry Pi with Octoprint again and reinstalled Cura from scratch.

It still crashes into the print each time. It did look like two of my prints failed at the same height, my most recent ran over 14 hours before failing.

Also, the failed print looks great right up until it shifts. The print is smooth and without any layer squishing or gaps, and then it shows maybe a 2-3 mm shift where it was knocked over or damaged.

The motors measured about 55C as I measured them on the most recent fail right before I cancelled the print.

All I can narrow it down to is that something in the Rambo board has fried or damaged (maybe a motor stepper driver?) If it is overheating a stepper driver, it does so at different times (sometimes the printer runs for 7 hours, or sometimes 14 hours before failing). Maybe a stepper driver is damaged to somehow become very slightly unreliable?

The most recent print also knocked over a portion of the print and I could see melted white PLA on the side of the heat block, but it didn't actually ruin the right side of the print as the printer was still printing it perfectly.

Is it time to get a new board?

Edit: I decided to order a new Rambo to check the board. I will swap the board when it comes in and update this thread if it is successful.

Have you tried printing from SD instead of from Octoprint to rule out the Raspi?

Is the fuse socket loose? Maybe things heat up enough over time that it breaks contact.

I used an Xacto knife to 'retension' the tabs that my fuse went into because I was having a similar intermittent heat/power issue, and that did the trick.

Option B is to solder in a wired automotive fuse holder. That toes the warranty voiding line, though.

I'll check these when I have a chance. I wonder if when I replaced the fuse, I bent the fuse socket a little wider than it should have been.

I got the new board in last week and went ahead and replaced it. The printer works perfectly now. I'm not sure if it's worth unwiring and rewiring to try and diagnose the old board, but it can definitely be isolated to something on the board (loose fuse, bad motor driver, etc).

printering wrote:I got the new board in last week and went ahead and replaced it. The printer works perfectly now. I'm not sure if it's worth unwiring and rewiring to try and diagnose the old board, but it can definitely be isolated to something on the board (loose fuse, bad motor driver, etc).

I am glad you got the new board in and it fixed the problem.
Happy Printing!