So I’ve brought this up and been ignored by Bambu. Here is the issue I’ve been having on my P1S since the 1.04 update. No error messages ever appear. This only happens when printing ANY object over 180mm tall because the bed lowers to the bottom to allow removal. When that happens it loses it’s Z axis home EVERY time. When it loses the Z axis home, it won’t let me manually raise the bed off the bottom with either the display, BL studio, or the app.
Here’s a link to the video. BTW, I can’t find the instructions on how to embed a video. You can hear what’s going on. I’d like to get this resolved before it destroys the printer. And, yes it is that loud. My wife can hear it on another floor in our house.
Z axis home issue P1S
Yes, I’ve seen that issue as well, but what helps me is to home the bed immediately after the print is done.
Doesn’t help.
Did a factory rest and for the first time it fails the initial test.
This time I’m opening a ticket with the video, log files, and self test failure code. Interesting how this was never a problem for me until the 1.04.02 firmware upgrade.
Also interesting that the date stamp on the log files for failing the test is 1/1/1980, and all the other files are the actual date and time.
What also sucks is I just received my AMS, and now the printer is dead in the water. If the display, Bambu Studio, or the app would allow me to raise it off the bottom, I’d be able to get it to work, but that option is blocked w/o a Z home.
1 Like
Have you tried to raise the bed by hand? Turn the screws by hand till its at the top and try again.
1 Like
No, did not know you could do that. Is there a way to turn all of them at once?
Tip the printer on its side and move the Z belt by hand.
1 Like
Issue resolved in 2 steps.
Got the plate to finally move up. Found a thread on this in the reddit bambu section.
One user had been told by bambu tech support to lift the bed, loosen the 2 screws at the bottom of the z axis rods, and then re tighten them until just snug. Did that and the problem no longer occurs.
However, because of what happened, the bed was a hair off level. Flipped it on its side and inspected the belt to ensure it didn’t have any damage. Then used my finger to relieve a little belt pressure on each rod gear, then rotated it in the down direction until it stopped. One rod rotated more than the others.
Flipped it back over and started it up. Did a Z axis home and it only made the grinding sound for less than a second before lifting the bed off the bottom. Since then have not had the problem re occur. 
The printer still losses the z axis home whenever power is cycled. This would appear to be a firmware bug.