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Cohen

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Cohen last won the day on May 31 2016

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  1. Hi Randy, yes it are the same resistors. Also R102 and R103 for the extruder steppers.
  2. I have read the nophead article a long time ago, but I never knew the print results were this good. We have not found the time to properly test this yet, I hope we can do this in the foreseeable future, so we can implement this.
  3. I don't know any Patrick Olma, the question did not come from Ultimaker (weird coincidence timing wise though). They are still saying the voltage needs to exceed 5,5 volts to damage the chip, which it doesn't during normal use. Tying the enable pin to 5V might be a good idea though. Another possible reason for the chip breaking could indeed be esd. The best advise I can give you is to use the printer in a more traditional setup (original psu, not grounding the casing), and see if that fixes it. EMC can be pretty hard to grasp, and is hard to troubleshoot when not on site. I would however like to see a simple diagram of how your printer, psu, grounding etc. is connected together. Maybe I can give you some better grounded (Pun intended) advice. :-) I will fix the chip pin-out on an upcoming version of the Ulticontroller, but it takes some time before it will be ready for production especially with al the current stock we have.
  4. It turns out you're right umagi, the chip is not connected as it should be. I never noticed, these chips are often symmetrical, so it doesn't matter which is the high side and which is the low. It should not, however account for the chip breaking. The 5V is still below the recommended operating voltage of 5,5, and well below the absolute maximum of 7. Going over the 4,4 volts of the design requirements shouldn't break the chip. If it did, we would see this issue much more often, but we don't. Did you check your voltages with a multimeter?
  5. Sounds good! Nice results! This design was before my time, but I know we've had issues with it. That is one of the reasons we switched to a PT100 for temperature measurement in the UM2 and UMO+. Because the UMO is no longer in production, we only have a small stock left of these boards for spare parts. Therefore it's not worth it to upgrade it I am afraid.
  6. Nothing to worry about. It's heat discoloration like neotko said. The steppers get pretty hot, and unfortunately the white soldermask changes color under the high temperature over time. A fan is not needed, but couldn't hurt of course.
  7. I worked around this by temporarily setting the Z maximum height at a greater value in Machine settings.
  8. For those interested the Altium design files and the schematic can now be found here: https://github.com/Ultimaker/HeatedBedUpgradekit Hey Anthony, it would be great if you can send the board back. If you can let support know when they contact you that would be great. Thanks! Coen.
  9. The circuit which switches the bed on and off is the same as on the Ultimainboard. The FET can fail if it is shorted. Unfortunately the failure mode of a FET is it stays always on. Turning the printer off while the bed is on should not cause any problems. It is important to keep in mind to always disconnect the power before performing any maintenance on the machine. When the printer is turned off there is still power on some parts of the machine. The 24V to 19V circuit stays on and there is still 24volts on the bed, it is just not pulled to GND. I will look into this and will let you know more soon. You can contact support for a new board.
  10. Did you check if the cables were firmly screwed down in the connector? Is there any damage visible?
  11. Here is a screenshot taken with the thermal camera with the board under extreme heat stress. The board is taped to a heated bed which is at 100C, with all motors connected and powered, and the XYZ stepper current set to 2000mA (E to the standard 1250), to get them as hot as possible. Cold start current is 1,03A, again measured with a multimeter through one coil, with the motor powered and set to full-step. At the highest temperature the sense resistors themselves got to 116 C, with the current dropping to 0,936A. And while it's not nothing, I think the resistors hold up well at such high temperatures.
  12. By the way I will continue testing to rule it out, but I don't think the resistors are the problem. Even with a big fan blowing air over the board Illuminartis test starts visually failing at 5mm^3/s
  13. Hey Guys, haven't forgotten about this post, took me a while to catch up reading though :-) A couple things: The current settings in Marlin doesnt match the actual current precisely. It was some time ago since I last measured motor power, so I set up an Ultimainboard, set the stepper to full stepping, powered the motor and meausured 1,03 amps through the coil. I attached the board to a heated bed with heat conducting tape and heated it up. I got the sense resistor up to about 73C (measured with the awesome thermal camera borrowed from our Swedish friends Daniel and Anders, thanks guys!), and the current dropped to 0,96A, so that's a drop of 70mA. That was just a first test, I want to stress the board some more, I agree these tests should be done at the highest temperatures the board could reach. I'll keep you posted. Another test I want to do is run a few prints with and without cooling the board and then measuring the weight of the printed object to determine a change in extrusion, so also more on this later. About damaging the resistors when subjected to heat (70-80C) for a long time, I dont think this would quickly cause problems if the datasheet advertises the maximum operating temperature is 125C. If anyone has any suggestions for tests where an Ultimainboard might be damaged, and you dont want to risk your own, you can post it here. If I think it can be usefull to figure out the cause of the problem I can do it, we have spares here as you might imagine :-)
  14. Hey guys, I was notified to this post and I will look into this today. I will run some tests, do some measurements and plough through some datasheets. I'll keep you posted. (I'm the electrical engineer at Ultimaker for those of you who don't know)
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