First problem on pretty new printer
I have bought a prusa MK2S some weeks ago, after some calibrations i got pretty good prints and reliable results, but on my last print i noticed a missing layer near the end of the printing process 
(Good print from 2 days ago) so i said to myself "let's see if the belt has any problem by testing something today"
This is the result 
(today's print) the first thing i thought was that the PLA absorbed water by searching around the subject on the internet; but i would like to know what people with much more experience think about the problem i'm having.
Re: First problem on pretty new printer
It looks to me like you have a partial clog in you extruder.
Try a "cold pull" or run some cleaning filament through it.
Check the section "Extruder stops extruding filament. (Works for a while then stops)" here:
Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…
Re: First problem on pretty new printer
It looks to me like you have a partial clog in you extruder.
Try a "cold pull" or run some cleaning filament through it.
Check the section "Extruder stops extruding filament. (Works for a while then stops)" here:
Thank you a lot, after I opened the thread I tried to change filament to no vail since I got the same result, so I changed back the old filament and made it run to get a clean color, at that point I tried printing buddy in hope that maybe the problem was in the extruder, and in fact I ended up with a perfect print.
The only problem is that after that perfect print (not even 20 minutes ago) I tried again to print my desired object, with the similar bad results I got from the frog, could the filament still be partially clogged (even after a perfect print) ? or it's my g-code just problematic ?
Re: First problem on pretty new printer
If items from the SD card print well and yours don't you have a bad slicer settings. You need to tell us what you are doing there.
Also, check the tension on the extruder screws. They should be 14mm out with no filament in.
Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…
Re: First problem on pretty new printer
Ok, this is the object and the options 
and also the gcode https://www.mediafire.com/file/mjzm9mbi4h2xxax/right_arm_PLA_ULTRADETAIL.gcode
EDIT: I tried printing a whistle and the feeding mechanism was making the typical noise of a stuck filament, yep i probably have an extruder\feeding problem, do you have a video or a guide that shows how to get the tension perfectly right ?
Re: First problem on pretty new printer
The tension should be easy. Make sure the washer is 14mm from the plastic body - when there is no filament installed.
If the extruder is clogged, you need to clear it. Heat it up to a bit more than your normal filament 220C, and try pushing a small Allen key down to push out the filament and make sure it is coming out in a nice clear line from the nozzle. Search "cold pull" and try one of those.
Please ZIP your .stl file and post. I can try to slice it.
Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…
Re: First problem on pretty new printer
Ok the tension should be right now, i will clean everything tomorrow.
Here's the file https://www.mediafire.com/file/06z2sus15q7we0v/right_arm.zip