Upper layer problems

I have rebuilt my Mini 1 - a 4 or so year old machine. I replaced the extruder thermistor fixed a broken wire in the lower drag chain - one of the purple ones for the bed heater. I got the machine working again but lousy prints with pillowing on top an horizontal ridges on side walls. I have determined that most of the issues were my Z drive. The leadscrews were not fully aligned and I have done that now with a digital caliper, and the Z offset also needed adjustment. I also played with print settings but have gone back to default settings for ABS. I always end up there because that is where my best prints in the past which were generally excellent were.

After much experimenting I am getting first 1/4" height is excellent then I get separation of all the layers above.Test

Should have added - I am desperately trying to solve this issue and apart from fine tuning my Z offset maybe I am out of ideas. Any help is most welcome.

So its good for the first 1/4 inch and then it starts to seperate… does it seperate more the farther it goes? If so it could be that the motors z step is out of calibration. This would mean it thinks its moved up say .25 mm and in reality its moved .255 mm. While the distance means nothing at first the longer you go the farther off it gets. 1/4mm is 6.35mm so if you are using a standard 0.25 layer height you will have gone through 25 layers you are now off by .25mm, a whole layer. If you think this might be the case then you can try to calibrate your printer… that being said you should watch TS’s video about trying to overcompensate…https://www.youtube.com/watch?v=Mbn1ckR86Z8. Just a note, if you do this PLEASE, write down your original settings so you have a base line. That being said this is a decent alternative to the cube method to see if your settings seem close: https://www.youtube.com/watch?v=ZfqeTzc3NpM

Thanks for your input. I subsequently had managed to print a 20mm test cube quite successfully at an extreme corner of the bed - so I think I am probably good on Z-axis alignments and Z-offset. This cube had no delaminations although still getting some pillowing on the top layer. I tried a full bed area print last night that failed midway - appears maybe a filament feed problem now. I am chasing problems around at the moment!

Glad to hear you found something to head you in a forward direction!