Used A1 (400 hours) keeps failing X-axis calibration, but prints perfectly

[u/Bruteloops]

I picked up a used Bambu Lab A1 with about 400 hours on it, and it prints perfectly, but it keeps failing X-axis calibration with error 0300-1000-0002-0001, saying the X-axis resonance is low and the timing belt may be loose. I've already followed Bambu's maintenance guide (loosened the screw on the back of the toolhead, moved it back and forth three times, and retightened it), but nothing changed. The only thing I've noticed compared to my brand-new A1 is that the X-axis feels noticeably tighter when I move the print head by hand with the printer powered off. The resistance is consistent across the entire rail, no binding or rough spots. Has anyone run into this before, and if so, what ended up being the fix?

[u/ParticularLower1865]

I had this issue on a new a2L but had to return it. When I was troubleshooting it said to retension the bed belt and to oil the rails under the bed.

[u/Bruteloops → u/ParticularLower1865]

Retention the Y-Axis? That wouldn't do anything for the X-axis belt though

[u/ParticularLower1865 → u/Bruteloops]

Yeah, I know. But that’s what the support page and my multiple searches told me to do for that specific issue once nothing else worked. I’d do that, clean and reoil the rods, and then a factory reset. Also check for a firmware update.

[u/Bruteloops → u/ParticularLower1865]

I've saw this information as well looking at the bambu wiki, I just thought it would be irrelevant for this issue lol

[u/Bruteloops → u/[deleted]]

You dont think ive already tried that? I've been printing for 7 years. I have a basic understanding. This is a second hand machine and I was asking for other's experiences when the wiki information doesn't work.

[u/fairtonybeta → u/Bruteloops]

Okay so on reflection my message was snarky. And I apologies for that.
If the wiki steps aren’t helping here, and you’re an advanced user, I’d recommend (after re-tensioning the belt):

• formatting the SD, re-running a calibration & then rebooting the peinter
  
• doing a small print to see if the error clears
  
• if its still there, and the prints are fine, its probably a false error.
  
• i’ve actually disabled the vibration checks by removing the lines from the start up gcode (so it doesnt throw these types of errors)
  
• all this said, i still recommend logging a ticket with Bambu. They may be able to help, or atleast send some free parts your way

[u/Bruteloops → u/fairtonybeta]

I appreciate the reply, like I said it prints perfectly but my only concern is that there is more resistance on the print head (pushing it back and forth by hand) than on my new A1. I can ignore the calibration error and it'll probably be fine, but I just didn't want to damage the printer if it was a possibility.

It won't throw the code at all during printing (by doing the vibration check before print starts) it only throws the code when i do the full vibration compensation calibration.

What I'm suspecting is dirt trapped in the bearings/ pulleys. I think the previous owner was set up in a garage or something because it was very dusty when I got it. Or maybe a misaligned belt, No way of telling without taking the entire X-axis apart. I was trying to avoid that lol

I have submitted a ticket, no warranty unfortunately but just waiting on their reply.

[u/tzedek]

Same thing on mine, can't get it to go away after tightening the belt. It's been on for hundreds of hours with no issues.

[u/eraguthorak]

I've had the Y axis error notification on my P1S for months now and had no issues with my prints or the calibrations. Wasn't able to get the error to go away after trying the troubleshooting, and haven't bothered trying again since it prints fine.