I was playing a survival on Uranus for 40 minutes with Nekros Prime + Despoil augment + Smeeta Loot Kavat and there was no ash systems ready to be picked up.
I know there are other ways to get it, I tried them all. Defection, Disruption, Defense, Survival, Kuva Lich missions, Kuva Flood, Kuva Siphon and Sortie
I don't know anymore how to get ash systems. Feel free to give me some tips and tricks on how to get that one specific part.
Start Kelpie (Sedna) solo or with a squad
Play the mode as normal until you see Pack Hunters. Let the demolist destroy the conduit (Pack Hunters)
Just try to survive and the manic's are spawning slowly but it's the best and easiest method for me.