what is ithis - skipping outline ?

my prusa will do this thing where it prints fine , then for 1 slice it just doesnt do the outside border of a part , i end up with well printed infill , and a missing outside row ..
my camera does large pictures so i'm just putting a link to where the pics are (only 2 pics) and also my slic3r config.ini

[www.lucindrea.com]

i dont know where to start to look , is this a slic3r error? or somthing mechinal with the printer it's self .. i dont know what other info to post here that may be helpfull so please ask if you need to know anything , but be aware i'm about to leave for the weekend and wont be back till sunday night so i may not be able to get the info up right away.
What i will put up real quick is that i have a prusa i2 , bowden print head (w/4mm fan) , i'm useing PLA at 190' on a headted bead of 60' also that this is a fairly new issue - because the border is missing on the ENTIRE layer , i think this is slic3r related (v 9.10) .

Is it one specific file or does it do it on all your prints ?

seems to be all my prints recenty .. and it's random .. some prints are a hot mess , others only 1 or 2 missing lines. .. i would think if it was somthing with the extruder sticking or somthing allon those lines it wouldnt be just to outside border , same goes for all mechinacal problems i can think of.

Try printing a gcode file that you sliced before this became a problem?

If it was skipping randomly I would say its extruder issue or bad filament but if it only does it durning outlines and not infill ever then it may be a g code issue can you recall anything you have started doing differently that could pinpoint the cause of it ?

Have you checked whether the filament spool can spin freely or if the filament snags up somewhere between spool and extruder?
Or have you checked the Extruder motor driver?

I once had similar looking problems, Infill looked fine while the outside was messed up periodically. Turned out that the Extruder motor driver was shutting down every few layers due to overheating. I guess the effect isn't noticeable that much in the infill because there is a lot of already laid down material to compensate.

One thing that has helped me is settin up my printer on my coffe table. Put it on a towel or something to dampen sounds a bit and print away while you watch TV/internet/whatever, that way you will be able to "catch it in the act" and hopefully resolve the issue.

i may try with the towel later it's a good idea .. and it is possable the spool could stick , the holder i have isnt the best.

think i've worked somthing out .. it looks like the print head temp is droping to like 150C mid print .. dont know why as the led for the extruder heat is on .. .. possablyl loose wire?

lead for extruder just indicates it is trying to warm it up. likely the issue is with the heater wiring. look for shorts as well. of course there is the fact that there is a built in temp minimum for extruder to work, so if the temp is ok , and the thermister is incorrect the temp may shut down as well.

I would rewire the thermister first, and if issues persist look at the heater, then look at the power supply to be sure it can push the current and has not been damaged.

just a fyi - looks like a combo of slic3er settings and angle of fan hood - my fan was blowing to hard and cooling down the head faster than it could keep up .. i didnt think the fan was that strong but i guess i was wrong ... i have tweaked it so it only (mostly) comes on during bridges.