Newb here. Z calibration fails repeatedly
New to the 3d printing game so I apologize if this has been asked before.
I opted for a used upgraded mk2.5s with the half bear mod and an enclosure because I have heard that the PRUSA printers are extremely reliable. Well the only thing I can get it to do reliably is fail calibration.
At the advice of the seller, I ran the Wizard when I got the printer setup at home. Everything seems to work well until the z calibration. I’ve tried to adjust the Pinda probe and I was able to get it to start the process of calibrating the z axis once. But on the way from point 4 to point 5 the print nozzle scratched the bed. Not sure how much of an issue that will be but it doesn’t matter at this point because I can’t get it calibrated at all.
After the calibration fails, the z height defaults to 5.0(mm?) I’ve used the credit card trick to set the Pinda height. At that height the Pinda sensor triggers at 4.0(again, according to the defaulted z adjustment menu). But it’s very touchy. Sometimes even sliding a piece of paper on the plate can trigger it without touching it. Also the Pinda seems to be slightly outside of the first circle. To check for consistency, I manually moved the head and bed to position 4 and to be the Pinda to trigger the z had to be at 6. This lead me to check if the bed is warped. I used a straight edge and I can slide a piece of paper under it in several places and positions.
I’m not sure how else to troubleshoot this but I’m open to any and all suggestions and advice. Thanks in advance.