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I don't think you had a clogged nozzle. I think the filament was stuck on something inside the print head. This happens a lot and I just move the filament up a few mm and then back down and it suddenly goes much farther. Moving the print head to another corner can also help. When I put pla into my machine I always cut off the tip to get some fresh pla and to let the feeder grip a new spot on the pla. I always cut at an angle twice to make a chisel/pointy tip. If you ever do get a clogged nozzle, do the atomic cleaning method but no need to remove the bowden - just set the nozzle to 90C and pull hard. The feeder stepper offers almost no resistance. Also let the filament cool in the bowden for 10 seconds before pulling through the feeder or it might break off inside and then you have to take it apart. :(

Hmm. Just a coincidence? That's very strange. Maybe there is a slicing issue - I've seen many slicing related bugs but this isn't one I'm familiar with. It's really hard to believe this is a slicing bug but still, knowing the path the head takes can be informative. I'm guessing these spots are where the outer shell starts? Maybe? Seems unlikely though. Go back to Cura and look at this region of the part in layer view - half way through this "bad" region. Are there movements related to this area? Blue movements? Could you post a screen shot? I still think if you simply lower the speed to 35mm/sec it will look much better and those tiny holes will disappear. And regarding leveling - yes you probably need to tighten all 3 screws by about the same amount and do the leveling procedure one last time. Then adjust without the procedure afterwards (just turn screws a little if it's a little low or high while printing skirt - that's half the purpose of a skirt). Once you get leveling perfect you can leave it alone for weeks at a time.

That's fine. I usually print 220C/60C for nozzle/bed. You can probably leave the bed at 60C for a year and never touch that. But the nozzle temp varies a lot. If you are in a rush and want to print something low quality you can print much faster if you print at 240C. But if you want to avoid stringing (not an issue for your knob) you have to lower the temperature to prevent the nozzle from leaking when it is spanning a gap to print some tower or something. But if you lower the temperature now you have to print slower.

How do you even "hold" a button down and drag at the same time with a mouse pad? That's what you need to do. Anyway on a mac "ctrl" while clicking is the same as right mouse button on a PC. So if you can hold down CTRL key while you click and drag does that work? Also try arrow keys as suggested above.

He means if you lower the temperature without lowering the speed you might get underextrusion due to the toothpaste nature of colder PLA. We call them "strings" or "stringing". Now you know what to google. Here are some hints - first photo: http://umforum.ultimaker.com/index.php?/topic/1872-some-calibration-photographs/

Be gentle - the traces built into the board are very thin and it's easy to damage/rip them off. The snip method is superior. Remember - even if you can't get the old pins out you can solder the new pins to the old pins. But don't - just pull them out gently rocking them back and forth after the solder is hot from the other side. Apply liberal amounts of solder to let the heat flow nicely.

What is this? feedrate percent on controller? flow rate?

Those holes by the letters are normal for this print. That is expected. This is a special test and is printed at very high speeds. You normally don't want to print that fast if you want a pretty result. Your printer passed the test perfectly. Is it slipping backwards when it clicks? The dark blue line on this graph shows absolute fastest possible print speeds: http://umforum.ultimaker.com/index.php?/topic/4127-um2-extrusion-rates-revisited/ I try to never go faster than half that speed. Reading off the graph you can go 70mm/sec at .2mm layers which translates to .25/.2*70 or 56mm/sec at .25mm layers. So for .25mm layers and 217C I would print at 25mm/sec. Or you can stay at 50mm/sec and raise the temperature to 250C but I don't recommend going over 240C. 240C will be hot enough to print at 50mm/sec .25mm layers. Note that the quality isn't as good when you print faster XY speeds. For extra good quality you want to print 20-35mm/sec. But if quality is "good enough" then print at 25mm/sec 217C or 50mm/sec at 240C.

DSM does threads, yes: DSM's big strength is it's push/pull feature. If you select a face there about 10 different ways to push or pull it. It's a strange way of doing things and very powerful. So threads are done with the pull feature - spiral pull: http://www.rs-online.com/designspark/electronics/eng/knowledge-item/designspark-mechanical-thread-creation

What's a thread? You mean cpu utilization? It runs very fast on my machine. I don't know about threads. All cad packages have a large learning curve before you can make say a door hinge in 3 minutes (as you should be able to!). It's very frustrating. I'm getting much better at DSM (design spark mechanical) and really loving it. I can see that one day I will be faster at DSM than sketchup. Probably a few years from now as I only design 1 thing per month.

Yes. Oh - wait - you want to know how? I'm not sure how. I did it but it was difficult. But that was back in December. Now the firmware has fixed at least 2 bugs in this feature. Basically there is a CUSTOMIZE option somewhere in the material settings. It took me about 20 tries to save. After you save your changes you have to choose *where* to save the changes. I didn't understand this the first 10 times. So you pick PLA to save into. If this doesn't work create 2 or 3 custom filaments and then go back and save into PLA. Other people reported not being able to save into PLA until they created 2 custom filaments first. Still others reported that if you power cycle you lose the customization unless you do something with the lights. I didn't have that problem.

On UM2 menu system: ADVANCED MAINTENANCE MOVE-FILAMENT. Something like that. Move it backwards. If it won't go backwards then you ground it. Heat nozzle to 180C, cut power, pull firmly on filament out through the back. Although if it isn't ground I usually heat nozzle to only 90C before pulling it out. The feeder motor offers almost no resistance when moving filament by hand. As long as it isn't powered (which is almost always if you aren't printing but difficult to predict).

By the way heating to 260C can be counter productive and just make more gunk. 180C is plenty hot for nozzle cleaning procedures. If the atomic method isn't enough you can remove the nozzle and burn it all out and then do atomic method. Or soak in acetone for an hour. Also visually examine your bowden tube for tiny pieces of old ABS carried along by the filamant.

I just use my fingers. Haven't gotten burned yet. curling filament touching tip is normal when it first comes out but if 50mm of hanging filament isn't enough gravity to keep it from touching tip then you need to clean the hole in the tip by sticking a needle in there and swirling it around. Atomic method is easiest and fastest way to clean. Switching from ABS back to PLA will always need a TON of cleaning and the atomic method is best. I now do the atomic method without removing the bowden I just force the filament in through the feeder and pull it back out through the feeder. Atomic method: http://umforum.ultimaker.com/index.php?/topic/4118-blocked-nozzle/?p=33691

Need more information - there are too many causes. Often there is just a small air pocket in the nozzle and if you wait a bit the filament will come out. Is the feeder moving forward (black thing - back of machine)? Can you see the filament moving? One possible (unlikely) failure that happens sometimes: the sleeve on the feeder is too loose so that it won't turn. Another - the filament got ground up (consider tightening the feeder a little - see Robert's guide - I linked to it above - post #13).

Some curling is normal - if you pull it down a bit and let 50mm of string hang below the nozzle and then extrude some more will it fall straight then?

Rafael - what country are you in? This is important to get faster service. Please update your profile settings "location" to indicate your country.

It sounds like you replaced the wiring and the motor. It could still be limit switch related or it could be the controller board. You need to prove to support that you have it down to the exact problem. First install pronterface and hook up your computer to the printer through USB so you can get much more fine control over your printer: http://koti.kapsi.fi/~kliment/printrun/ Pronterface is a wonderful utility that lets you control the printer so for example you can read back the limit switch settings or move a single axis by 1mm or whatever. With power off, remove the bottom cover and disconnect the Z endstop cable to see if this is preventing Z axis from moving. Leave cover off and power up the machine and connect with pronterface. With pronterface move all 3 axes 1mm (don't home Z axis). Start with X axis for practice - move it 1mm at a time. Then try Z axis. If it still won't work then it's not the limit switch. If it is now working then something is wrong with this switch - test it with a multimeter. If it's not the switch and motor still does not move, swap the cables for the X and Z stepper motors. Try to move the Z axis by telling pronterface to move the X axis. If the Z axis now moves then the problem was with the Z driver. Explain this test to Ultimaker and ship the board back to them. Report here the results of these 2 tests please.

Not me. But probably someone has it. Certainly at the UM headquarters. I heard there is some major problem with over-temperature or something - maybe the 3rd fan isn't enough to cool two nozzles?

Please check out Robert's new wonderful guide: http://support.3dverkstan.se/article/23-a-visual-ultimaker-troubleshooting-guide

The 3rd fan is in the back of the print head. Look at the print head very carefull. Feel for a breeze. It's very quiet but it comes on as soon as you power on (even before the lights). Set the level where the fan comes on in Cura - I like to have it on full by 1mm. Default should be 5mm. It will come on gradually so as not to mess up the nozzle temperature controller with a sudden change in heating requirements. Make sure fan is 100% min and max. nozzle temp, bed temp, retraction distance, retraction speed are all controlled on the UM2 itself (usually - there's 5 ways to control temp). On the UM2 you can select what temp to use for PLA and change it and save it back into the PLA material memory position. Or you can just hit PRINT and before it starts printing you can go to the TUNE menu and change the nozzle and bed temps there. I recommend 5.5mm for retraction, max retraction speed (35?), 220C for a good medium safe average nozzle temp (190-240 are reasonable printing temps depending on print speed). Oh and bed temp should be 50C to 60C.

Um - off topic question - sorry but it's kind of a lot to read - many hundreds of posts: http://umforum.ultimaker.com/index.php?/topic/3976-almost-always-missing-layers-underextruding/ Definitely read this first post: http://umforum.ultimaker.com/index.php?/topic/4586-can-your-um2-printer-achieve-10mm3s-test-it-here/ And some interesting solutions (although I haven't modified anything on my UM2 and it prints fine): http://umforum.ultimaker.com/index.php?/topic/4393-ultimaker2-feeder-system-improvements-and-ideas/

Does the feeder have a metal ring/collet at the entrance now?

This is a double posting - please refer to the other posting here. I'm closing this topic so just go here instead: http://umforum.ultimaker.com/index.php?/topic/6591-first-print-um-robot-some-issues/

The unconnected cable is for a second extruder which I assume you don't have as it's not for sale yet.