Welcome to the SeeMeCNC Community

I'm not even sure where to start. . .
I bought my V2 years ago, and as with most people, went through the usual learning curve. I learned to manually calibrate and set it up (not a complex task i felt) and was printing decently with ABS. I had to babysit it a lot and had a print failure rate of about 60 percent. I eventually upgraded to PEI and the injection molded carriages and ball arms. I also move to an e3d V6 with .4mm nozzle all mounted on one of 713 makers' mounts with a yellow-jacket board. My biggest issue was getting it to hold temp some of the time and having PID calibration wanting to go cookoo all the time. I was getting to a point where I was usually successful, loosing only about 1 in 3 prints.
Life got in the way as it tends too, and the printer sat untouched for a year and a half. I recently got the spark back and decided to completely overhaul the wiring. Once I got done rebuilding, I ran temp calibrations and I was super happy with how stable and quickly it reached and maintained temp settings. Then I went to actually print something. . .

I printed one single layer circle to check for level, and while it didn't fail entirely it wasn't amazing. Since that circle I haven't been able to print anything. Using the same filament again, it just spit out dots on the bed and wouldn't start to really put out anything. I figured it was the old filament, so I changed to a new roll of abs. same problem, i couldn't get a first layer down. I decided to clean out the hot end and try again, and no luck. I went back and completely re-calibrated and leveled. Still no go. So then I decided to switch to PETG for the first time, because i figured why not. It just rolled around the nozzle and made a mess. Lowered my Z and tried again, same problem. I adjusted until my Z was basically zero and still nothing stuck. With everyone talking about how their prints always stick to PETG too well, I'm really confused. Decided to switch out nozzles for a new .5mm and still no change.

Lastly I went for broke and flipped the bed over to bare glass. re-calibrated and went for it. Still not a single thing. I had one potential moment where a half inch path of a perimeter stuck for a few seconds only to get yanked up by the building mass of goop on the nozzle.

I'm about to chuck this machine at a wall! Please, anything that could help I'd be willing to listen.

Sounds quite frustrating indeed. Do you mind posting some pictures and print settings, as well as making sure you've checked the belt tension, that the end-stops aren't loose, and that your extruder is calibrated. It does sound like you have some issues with extrusion calibration if you're having material accumulate on the nozzle while printing, but the others are also common enough issues if you let it sit. It could even be tower lean, or the top binding out of position if you tore the machine down that far to do the electrical rebuild.

Thanks for getting to me quickly. I'm gonna try to respond a s a check list to keep it simple.

Pictures - There's not much to see, as I can't even get it to start a first layer. but ill get what i can when I get back to it.

Settings - Filament settings were adjusted a lot to try and figure out the problem. never went faster than 30mm/s and ran every temp from 225 to 245. I haven't put a lot of time into extrusion calibration, mainly because i haven't had any results to calibrate off of. Diameter was set based on average of filament with calipers. tried small variations in multiplier with no luck. Extruder steps seems about right based on manual measurement making marks on incoming filament. Various other settings were changed accordingly, like nozzle size.

Belt Tension - I don't have a gauge but ever since I installed my custom version of the V27 tensioners it's never seem to be an issue in the past. of course I doubt it's absolutely perfect.http://forum.seemecnc.com/viewtopic.php ... V27#p77028


End stops - the bolts are tight and the only flex is the small amount from the weak plastic body, so nothing noteworthy.

Towers - I specifically made sure to whip out the square this time around. It wasn't perfect but definitely 99.8 percent level close. Best I can tell the frame is as lined up as melamine can be, though like many others, the bottom section top plate does bow up about half a mm over the LCD housing.

The only other thing I can note is that no matter how I calibrate or level, when it starts to print, the nozzle visually looks too high. almost like it's throwing out my Z adjustments. I've changed Z through LCD and through eeprom so not sure whats going on there.

What specifically should I take pics of? I have no prints to show, and there's not really anything left on the bed no matter how long I let it go.

In that case, can you export your slicer settings, as well as dump your EEPROM for me? Both should be relatively simple, as the EEPROM dump can be done basically by opening the EEPROM settings in mattercontrol, and copying the log as it loads them from the printer, while most slicers have a settings export tool. Pictures of the build up on the nozzle might help slightly, although if you're getting very little of the first layer to print, it's not too likely to help. Perhaps a close shot of any loops around the print itself it completes, or of the nozzle as it's laying down a track (this does require careful positioning, as well as starting a print that's likely to fail, so I understand if you don't) would be helpful on the picture front.

OK, so I had a long troubleshooting session last night and I think I'm getting somewhere.

This is what was happening every time. just a globby mess.
I re-leveled again, and started the print. It failed of course, so i added 50 microns to my z-max and tried again. I did this about a dozen times until something finally stuck. I'll list this attempt as the first attempt for simplicity. It was ugly and the skirt completely flopped, causing buildup and stringiness. I let it go anyway and it managed to finish the circle. The Y tower side was already detached by the end of the print so I just peeled it up from there.
I could tell it was obviously out of level, but the result surprised me because the Y tower was the tightest against the feeler gauge so I expected it to be the thinnest side. Instead it was the thick messy side, with the opposite end around 0.07mm thick. I measured the flattest part of the messy side at 0.21mm. I figured first step was to fix the level issue so I reduced my X and Z offset by 5 steps and added 5 to my Y offset. this is the next print.
This one was fairly messy as well but it was closer. The thin spot was still opposite the Y tower at 0.13mm with the Y side at 0.20mm. I figured I was on the right track so I repeated the process.
Even closer but still a mess on the Y side so I chose to only change the X and Z this time, as the thin side was now 0.18mm
The print never got started so I aborted and went back to adding 50 micron advances. It took three attempts to get another successful adhesion
That's where I am at the moment. I'm at work right now so I haven't had a chance to export my settings. BTW, dumb question, but how do I export slic3r settings? I know the eeprom part. I should note that for all these prints I was printing at 250c as apposed to the 245c from the other day. I may try 255c the next time I try. I also need to change my skirt settings. It's clearly needed to get the nozzle primed but I have to sit there and grab it with tweezers bit by bit so it doesn't sabotage the rest of the print.

screenshot of eeprom

What I ran into with the injection molded carriages was:

• When the nozzle bangs into something (e.g. the print plate), the blue injection molded pieces in the carriage that hold the wheel bearings in place separate.
• Once they separate, the bearings are no longer held in place, and there is slop in the carriage position. This manifests as e.g. rounded corners on squares.

Check whether your carriages wiggle on the rails.