Hello!
Since the support is taking their sweet time to answer (like a week by now), I might try my luck here. I tried doing the periodic maintenance on my A1, as described in the wiki. Turn out that one of the screws for the Z axis (one of these 2 in the pic below - wiki source) is loose (or whatever is the English word for it), basically you can screw it in forever, without feeling any tension/pressure.
I disassembled the frame and it seems there is a piece of plastic that is supposed to keep these 2 screws in place (image from wiki)
and it’s called ‘Z-Axis Tensioner’ on their wiki page (A1 Printer Frame Installation Tutorial | Bambu Lab Wiki). I didn’t get it out but it seems these screws are inserted directly into the plastic. Most likely that plastic is now gone for one of the screw, from friction or resonance or whatever (I didn’t screw in these ones before).
So, is there a way to buy a new piece? I didn’t find it on A1 parts list from Bambu shop. Is there a way to fix it? I was thinking of getting some metal nuts and heat insert them, but I don’t know if I would make it worse, or maybe there is a better solution than this. Thanks in advance and any advice is appreciated till the official support will give an answer.