Outer walls have vertical stripes/banding
What I can only describe as a “zebra” effect is showing on pretty much all the prints. Vertical lines are forming in the Z axis, where it looks like not enough filament is being extruded. Happens on the rear right section of the bed, just before the seam. First thought was Under extrusion, so I tried the following steps:
- Cold pull
- Increased the flow rate multiplier
- Adjusted the idler screw tension
- Replaced hotend PTFE tube
- Replaced the nozzle
- Replaced the Print fan
- Replaced the thermistor
- Replaced the Heater cartridge
Really running out of ideas here, and support is stumped too. Can be reproduced on Elegoo PLA and Prusament PLA (pictured). Printed on a Prusa Mini (FW 5.1.2) with Input Shaping (happens when it is disabled too although not as bad). 
RE: Outer walls have vertical stripes/banding
How thick is that near-vertical wall?
Please save your project as a .3mf file
Files > Save Project as
Zip the .3mf and post it here. It will contain both your part and your settings for us to diagnose.
Cheerio,
RE: Outer walls have vertical stripes/banding
After a bit more digging, I believe this is linked with this github issue, so I printed 5 cylinders, one on each corner and in the centre. back left, back right and front left cylinders where fine, however the front right cylinder was exhibiting the same issue. 
The 3mf file is attached. I received a sharp response from Prusa support basically telling me to stop contacting them about this issue, and are blaming it on the motherboard (which I highly doubt). Pretty much given up on the Mini, since my MK3S+ and MK4 have worked flawlessly.
One perimeter, zero fill, zero top layers printed five up - I'm surprised the prints were this good
For this sort of object use vase mode and print one at a time.
For a conventionally printed part make the walls at least three extrusions thick and form them properly in CAD so there is a proper exterior perimeter on the inside.
Cheerio,
RE: Outer walls have vertical stripes/banding
This effect was present on objects with multiple perimeters, 15% infill and 8 top layers, even with PETG. The above print was just to highlight it (as seen in the GitHub issue too). On my MK4, the same print was flawless. I was suspecting retraction settings where to fault, however I am still not sure. Any recommendations would be really appreciated.
RE: Outer walls have vertical stripes/banding
OK, some shower thoughts:
- looks like this is noticeable especially when print moves are in specific directions - especially from left to right, poeple on github reported that it looks like is caused by bending of the bowden tube between extruder and print head, but it manifests in whole gaps in the print and otherwise things look okay.
- But in here notice that the extrusion is not even, its not like the flow is not decreased but it changes to high/low/high/low so it is more like a jerks and not just that the filament stops, it looks more like filament is moving unevenly even if extruder is extruding evenly
- this means filament gets stuck in the bowden tube and is not moving linearly but gets some tension (causing under extrusion) and then it snaps after certain level (causing sudden extrusion) - this would mean it can happen in the tube (tube wearout) or at the edge of the bowden tube and the connection between the tube and the short PTFE in the heatbreak.
- another idea is to double check PTFE tubes before extruder and checking the friction of the spool, it should rotate really smoothly, because increased friction can cause resistance and can cause extruder also to work unevenly
So my recommendations are - REALLY look closely and inspect tubes on the path from extruder to the end of the nozzle
- if the PTFE is not used up (it should be round inside, and not oval etc check if there are no kinks, or something was flattened too hard (overscrewing), check if the tubes are cut straight flat and there is no gaps between the long tube from extruder and short PTFE tube in the heat break
- check if the short PTFE in the heatbreak is not used up and if it is in right direction in the heatbreak
- chek if the bowden tubes are not moving, whenever print head is close or away from Z axis
- same for metal parts, any change from one tube to another if there are any signs of wear-out
- check your heatbreak in general - see issues such as described here (see videos) https://github.com/prusa3d/Original-Prusa-MINI/issues/57
See my GitHub and printables.com for some 3d stuff that you may like.
RE: Outer walls have vertical stripes/banding
Just looked at my PTFE tube between the filament sensor and the extruder, and it was pretty rough. Managed to find a spare tube from my old MMU and used that in its place. I also checked the Bowden tube, and that was perfectly fine, nice round inner diameter, no kinks or anything. Checked the hot end PTFE tube, that was also fine too (reseated it again according to the replacement guide as well). Then torn apart the extruder and cleaned the Bondtech gear. Also gave the filament a bit more slack so it wasn’t pulling the reel from the holder. Tried printing the cylinder test again, yet no luck. I’m not sure whether the heartbreak is the issue, as some users with the Revo are also affected (assuming the heartbreak is different with the revo?)
RE: Outer walls have vertical stripes/banding
I print it 
whit Petg...Bondtech estruder and Revo hotend.....