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  1. Hi Fellow Ultimaker Hackers! I made a large number of mods to my UM2 almost as soon as I purchased it. The parts pictured below have seen <20 hours of printing time and are essentially new. Asking $100 + actual shipping for everything! (FYI just the hot end pack runs for $85). These are all original OEM parts. I am also listing this on Ebay so if interested, we can deal through Ebay so that you have peace of mind in buying.
  2. No I have almost never seen private sellers accept returns, however in case something is not right or was not described appropriately, honest buyer/parties work out a solution. If you sell via PayPal, I as a buyer would only purchase via PayPal Goods and Services. That means, you should take good pictures and list the details as accurately as possible. On receiving, if I as a buyer find discrepancies, I can open a dispute with Paypal and the resolution would likely result in the buyer sending the printer back and getting their money. As a seller, you can protect against fraudulent
  3. Aah!Sorry I misinterpreted your question. Very good question indeed. One hypothesis I had was the PSU could be 'faulty'. If you look at the derating due to temperature for the powersupply, it could underperform (and result in voltage sag) in warmer climates. Temperature wasn't an issue for my PSU. So it could be 1) I genuinely had a faulty/non-optimal power supply or 2) 220W is just isn't enough. I suspected the latter (could be wrong) because at its peak the printer consumes about 220-230W (190 peak heating, 35W peak extruder, 20-50W transients from motor).
  4. @geert_2: I measured it at the 24V connector: You are right about voltage drop over significant distances or over thin traces. With a high-impedance measurement (a voltmeter or oscilloscope) that is not an issue. The voltage drop over thin traces or long distances (aka high resistance) is V_drop = I*R. When making a high impendance measurement the I is very small and such drops are negligible (not zero). Second, it is irrelevant. Let's say I measure 23.5V instead of actual 24V. Goal of my measurement is not to measure exact voltage, but to measure the change in vol
  5. The source files for the firmware are here: Ultimaker2 source is here: https://github.com/Ultimaker/Ultimaker2Marlin Ultimaker2 plus is here: https://github.com/Ultimaker/UM2.1-Firmware You just need to download Arduino IDE, open the Marlin.ino file, and compile. To upload, connect printer to PC, select the right COM port, select Mega2560 as the board, and hit upload.
  6. Only one component is something I built/soldered. I am happy to make one for you at cost (I ended up with parts for several because of minimum PCB/Digikey/Mouser orders). That component is the PSU breakout board. If you don't mind a bit of a hack, you could literally cut the connector off a new power supply and just wire it to the rest -- you don't need it. I wanted the connector to look like factory installed at the back so I went the route of making a PCB. The Pololu G2 is something you can buy on Amazon (LINK to exact item I got). Again, this is a bit pricey but I over-engineere
  7. Hah, thank you for your kind words. I think, much like yourself, more than 3D printing, I enjoy perfecting it 😉
  8. This is super interesting. The image on the right looks very close to the issue I just resolved, however I would not suggest that is the cause because you had the printer working fine before you identified mechanical issues. My cause for prints like that was electrical and it would not just solve itself. It had to be there all along -- unless, power supply is degrading or is now being operated in much warmer ambient temperatures (causing wattage derating). Just for the heck of science.. can you reprint the same but with NO bed heat? Use Blue Tape to have the part stick.
  9. To bring closure to this thread, I have solved this issue for at least my printer. I tried several different software fixes such as PWM vs. Bang-Bang control of heat bed etc, and none were helpful for me. The issue as @Torgeir has pointed out is that there is a significant voltage drop. In the (poor) screenshot of the oscilloscope you can see the drop in the 24V line when the heat bed turns ON/OFF. The drop is around 400mV. With more time (and will) I wanted to figure out what subsystems are susceptible to this voltage drop (is it the ADC for temp sensors?
  10. Sorry to hear. Same here. My money is gone but at least here, the FBI case is still open. I also provided them with his TWO IP addresses that I was able to gather on my own accord. Those IPs are traceable to a unique mobile network subscriber and I am hoping someone does. If I do hear back, I will ping you so that you could have your police involved as well.
  11. Dear @rcfocus: Thank you so much for the detailed and elaborate response. I completely understand what you mean by a non-optimal grounding path. I think it does have to do something with noise (as @Torgeir also alluded to). See one more data point below. I turned the bed heater ON exactly in middle of the cube (so it was ON at 100% from middle to almost 3/4th way complete). No impact on quality, but as soon as the bed reaches it set_point of 60C and starts modulating ON/OFF, we see extrusion variations that correlate with the ON/OFF almost perfectly.
  12. Yeah I think this is some sort of stepping issue as well that happens as a result of current deficit. Maybe. I will look into ROSC, thank you for all those pointers! Edit: @Torgeir: I just read through that discussion about missed microstep. That is very interesting. I will try out the ROSC mod.
  13. Hi rcfocus, that is a great point, and I will measure the V rails to make sure. BTW, I am not sure what you mean by "ground level shifting". That is a term I've never come across and unfortunately unable to interpret. GND is simply a label reference for measurement purposes. In such a floating circuit what matters is the net potential difference, which should be 24V. Maybe what I interpret by ground level shifting is that when the power budget is exceeded, the power supply becomes current limited and is compensated by a reduction in voltage (i.e. 24V drooping). Even if
  14. Okay, so I went with the hypothesis: that the bed takes up plenty of power and that causes temperature variations in the extruder. As a result we see micro extrusion variations. Experiment The idea was to run a print job with and without BED_HEAT and conclude if there difference in quality and; if it can be attributed to temperature variations in extruder I edited my Gcode for Cube test such that mid-way into the print it would turn the BED_HEATER to OFF. I I collected temperature data as frequently as Marlin would print to Serial. I wrote a quick analysis scri
  15. That's right, but I think the PID loop is pretty slow, of around 7 Hz, so EMI isn't an issue as much. If really, I can shield the cables. Fortunately, electronics is in my wheelhouse so I will figure this out and report back for posterity in case someone has these issues.
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