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Posts posted by technolazy

  1. Update: I've finally chosen the lazy option and bought the last mark2 board the swiss reseller had in stock. Replacing a couple of transistors would probably have cost 60x less, but I consider this as a last tribute to this excellent project.  Incidentally, I also realized later that my original mainboard's stepper were not working anymore. Eventually the only option was to install a clone UM2.1.4 mainboard from China, with the driver for the #2 extruder still installed. That solution seems to work but I won't leave the machine printing unattended, which limits considerably the kind of work I can do with it.  As soon as I have some time to play around, I'll hopefully install a duet3d and have the tool changer work. Maybe.

  2. Hi, I have been an happy user of the mark2 with the expansion board for many years. Now I had to replace the ulticontroller (front board) and front OLED screen because... well I do not know exactly, but at some point on power on it smelled like electrical smoke and went dark. Now I could get a new ulticontroller from Ultimaker (via @Dim3nsioneer's shop) and I am on my way putting everything back together.

    But now the nozzle fan of the second printhead does not work.

    I mean, it never turns on, even if I warm up the nozzle above 40°C (or even 70°). I have the same modified thinkergnome firmware that used to work before (where the fan came online above 40°). I obviously checked all connections but could not see anything abnormal. The part fans with PWM on extruder #2 work as expected.
    With a multimeter I measured a mere 0.05 volt (but could be my multimeter running out of battery) at the "hotend fan" connector on the mark2 board. 2 questions:

    is anybody aware if recent revisions of the ulticontroller are still compatible with the mark2 expasion board?

    I did some more diagnostics...

    measured voltage on "hot end fan" socket with the cables to the hotend *disconnected*:

    below 40°C: 4.87v (but it should be 0?)

    above 40°C: 0.05v

    and with the hotend cable *connected*:

    below 40°C: 0.91v

    above 40°C: 0.02v

    So I'm a complete noob in matter electronics, but could it be that when the ulticontroller gave up (see above) it somehow affected some component on the mark2 board?

    I attach below the (I think) relevant part of the board diagram from https://github.com/foehnsturm/Mark2/blob/master/Mark 2 expansion board/Expansion board schematic rev1.jpg

    Is there a way to ascertain that the issue is with the mark2 board? If I could be sure that the problem originates from the mark2 board and not from something else down the chain (at this point that would be the mainboard, since the ulticontroller and the screen are brand new..), I'm almost ready to buy a new mark2 card ...

    UPDATE: thanks to the eagle files on github, I could physically locate the #4 pin on J1 : it is the one in the middle of the second row. I also checked that the fan works correctly by connecting it to the #1 hotend fan socket.
    I could do the following measurements on the pin4 of the cable coming from the ulticontroller:
    with fan cable *disconnected*:
    0v below 40°C

    4.85v above 40°C

    with fan cable *connected*:

    0.08v below 40°C

    4.85v above 40°C


    The signals 0v / 4.85v coming from the ulticontroller seem to be consistent with a pin low/high on the mega, thus a sign that everything is good on the side of the mainboard/ulticontroller, or am I wrong?

    If this is correct, is there any chance that this problem can be traced down precisely to one of the 4 components involved (2 transistors, 1 diode and 1 resistor)?


    Thank you in advance for any advice...




  3. Sorry, for some reason I was not notified of your message.

    Are you able to run the firmware "Tinker-Mark2-extended-expansion-board-17.06.hex" successfully?

    I have not tried and I couldn't try, because my machine is an UM2 not-extended, and I would like to avoid crashing the z-axis into the nozzle. This "x/y limit switch error" occurred for unexplained reasons then disappeared before I could identify a reason of even just a pattern.

    If you still encounter this issue, maybe you could ask the author of the firmware if he has any idea. Sorry that I can't help more.

  4. I installed it and am working on step 6 calibration.

    How to check if Mark 2 board works?

    What exact problem do you have at the moment? Is it still this one:

    The issue is 'nozzle 2' doesn't shows up in 'dual extrusion' mode.

    In this case, I would assume that something went wrong with the firmware update. As gr5 pointed out, there is no such thing as printhead auto-discovery.

    Are you sure that you picked up the right version of the firmware? Anything happened during the firmware upload process?

  5. Sooo,

    I just finished my first successful print! Even if there is still room for improvement in my settings, now my kids too have a cool traffic cone to play with :)(scaled down by 50%) :


    I’m deeply thankful to the incredible people that made this possible. My four years old printer is born again, once again (after the olsson block, a new feeder, and some other mods of my own). I’m still surprised and delighted by the power and the good of open source hardware.

    Now, to come down to some more mundane considerations, here are the caveats I encountered and how they were solved, in the hope that this can be useful to others. I stand to be corrected if any of the information below is not accurate.

    1. got a temperature error 01 as soon as the printer started. There was a short on the mark 2 expansion board, therefore the firmware was reading an extremely low value for the #2 temp sensor. => check the expansion board visually and if necessary with a multimeter, for shorts.

    2. was not sure which one of the firmware binaries from github I should chose. I used what I thought to be the most conservative choice initially (Mark2-dual-17.02.2.hex), but the fans on the printhead #2 were not working at all. This firmware does not work with the expansion board. With the thinkergnome flavor of the firmware it worked perfecly. This was confusing at first: when something does not work, one never knows exactly why, and it took me a while – and some unmounting and inspections of the cables & hardware – to understand that the problem was the firmware.

    3. I had occasional weird errors like « x/y limit switch error » while trying to perform manual homing. I guess this was caused by me switching between firmwares, performing factory resets and other calibrations. I calmed down, and this issue seems to be gone...

    4. I had the same problem as  MarcoUbtz with the printhead crashing into the front left corner upon tool change, and the solution by foehnsturm (set layer start at X{100} Y{50} in travel menu ) worked for me as well.

    5. I’m not the smartest guy on heart, but I did not realize immediately that the three options in the Cura plugin need to be activated (at least in 2.6.1).

    6. The cable of the feeder stepper motor that came with my UM2+ extrusion upgrade kit was just too short to route it properly to the mainboard. I cut the wires and soldered some extra 20 cm from another similar cable inbetween. Perhaps it would be nice to include an extension cable for the stepper in the mark 2 kit. (as a side note: could soldering the stepper cable and/or adding an extension cable cause electromagnetic issues? just wondering)

    The  instructions  on http://magnetic-tool-changer.com/ are outstanding for such a community project. I also found the cheatsheet posted by chiz on May 24th very useful. A link to it in the instructions pages would be very useful.

    As a side note, I used colorfabb XT white for the printed parts. And cyanilacrylate glue for fixing the magnets.

    • Like 6
  6. Findings:

    - with firmware Mark2-dual-17.02.2.hex, the head fan #2 never comes online.

    - with firmware Tinker-Mark2-expansion-board-17.02.2.hex, it comes online above 40°C.

    Is the former firmware not suitable for my particular setup (um2(+) with expansion board)? I can stick with the tinker firmware. But perhaps it could be interesting for others to know if the first firmware (non-tinker) is suitable for folks who have the expansion board. If it is supposed to work, maybe I can try to fix it.

    Another odd think I just noticed with both firmwares: Cura 2.6.1 (configured with the provided Mark2 printer profile), does not read any temp value for head #2. But via the UM display, the temp is displayed correctly. Is this a known issue?

  7. I haven't tried yet: I must have messed up something with the serial connection while trying to thinker around the issue via the Arduino IDE (I wanted to see what happens exactly code-side); anyways, I just noticed something: there seems to be a contact between the two pins on the expansion board:


    My multimeter, set to continuity mode, says that there is contact between the two pins. Which would explain why the firmware sees a very low value for the temperature.. (from what I can see in the firmware code, this error is thrown when the temp it reads is too low) am I seeing it right?

  8. Hi,

    I just installed the mark2 kit with the extension board on my 2014 (march) UM2, which has become a de facto UM2+ over the time (matchless olsson block, feeder 2+, 2+ printhead fans), using a second print head from a brand new UM2+ upgrade kit. Followed the instructions on magnetic-tool-changer.com and checked and rechecked again that all connections are done the right way.

    With the default firmware, the printer turns on normally, the values I read for bed and nozzle temp make sense (ambient temp more or less), and even if I haven't tried to actually print, stuff like nozzle and bed heat up and homing work as expected.

    However, when I install the custom firmwares (as per instructions), as soon as I turn the printer on, it shows the message "ERROR - STOPPED / Temp sensor / Go to ultimaker.com/ER01 . I re-checked all my connections again and again, and I do not see any discrepancies. I tried each of the firmwares available at


    but the outcome is still the same.

    I also tried plugging the #2 temp sensor into the temp1 position on the main board, while using the default firmware, but it works as expected (it reads plausible values).

    I'm running short of ideas...

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