Home position problem + goos skirt, but then pants :-(

[thegoodguy]

Hi all,

I just got my first printer; a AnyCubic i3 Mega S, and I'm using Cura 4.71

Aside from the test print (the owls), yesterday I did my first print of something of my own design using the same settings as the test print. It went really well and I was chuffed to bits. The end products are two supports that will clamp onto either side of my large, but slightly unusual dining table, and will hold a table-tennis net across the table. Today I started to print the second identical support. I made no changes. I used the same g-code file.

The original "home" position of the nozzle was over the plate at the bottom/left corner (where the nozzle would go down and then back up again to de-splodge itself). Now the "home" position has shifted to off the bottom off the plate. So now the de-splodging doesn't happen, because the splodge doesn't touch the base when the nozzle comes down. I have read and looked everywhere I can , but can find no instructions on how to tell the printer where home is. The Z limit switch is solidly fixed.

In addition to the above problem, something else odd and frustrating is happening now. The skirt prints well (the splodge at the start notwithstanding). After that, the first layer of the actual peice is pants . The printer seems to want to print the lines super-thin/non-existant. I haven't changed anything. Why would the skirt print (and adhere) perfectly and not the rest? I have re-checked the plate level and it is fine.

I've upload a short video to show what I mean about the pants first layer - https://youtu.be/HB2Mzcri6ts.

Thanks in advance.

Sud