3D Printing Problems (extrusion has gaps) - Disco Ultimate

Hi All,

Mostly reader here and finally created an account to post an issue I can't solve. Only an owner of 1 month and I have read some advices on here that I don't understand (so asking for layman terms in explanations please).
Please help me troubleshoot this issue :)
Settings:
Printer: Dagoma Disco Ultimate (single extruder)
Plastic: Geetech PLA White 1.75mm
Nozzle Temp: 210C
Software: Cura Ultimaker 4.4.1
Size: 0.2mm
Speed: tried fast and slow

Hopefully from the pictures you can see the problem (I posted an example previous day successful print of the same object). I was using Geetech PLA and switched to Chromatik, then realising it gave no extra printing quality for higher cost PLA I switched back to Geetech. However upon this switch, I had problems! I also included the 2 main areas that I have tried to clean.I have fully disassembled the rear feed cog and it seems to be fine, it turns and feeds plastic I believe so I cant see an issue there. I have yet to take apart from the nozzle section (actually I tried but I couldn't find how to completely take it apart, but if part of the troubleshooting requires it I will find out how).Thanks in advance!

Well I had a problem that had the same looks,
it was because when setting up a new slicer forgot to set the filament diameter.

As the default filament Dia is 3mm was getting under extrusion on all my prints,
after resetting to 1.75mm all worked fine again.

Attachment 14157