Prusa X Belt Not Working
I am currently assembling the Prusa I3 MK3S+ Printer kit, and am running into issues when doing the belt test for the X-axis. It keeps saying that I need to check the axis length. My belt status shows that I am currently at 250, however, the belt is very, very loose. Small adjustments on the tensioning screw have not helped, and I cannot get the belt status number to go above 250, despite the belt being very loose.
Please let me know if you need more information to help me fix this issue. Thank you
You may be able to take up a tooth or two at step 58 of:
https://help.prusa3d.com/en/guide/5-e-axis-assembly_169235
Cheerio,
RE:
Thanks for the response!
When you say "take up a tooth or two," do you mean that instead of putting 3-4 teeth in the x carriage, I should put 5-6, or the other way around (1-2 teeth)?
Also, would you recommend I re-tension the belt from the motor side or the idler side?
RE:
Thanks for the response!
When you say "take up a tooth or two," do you mean that instead of putting 3-4 teeth in the x carriage, I should put 5-6, or the other way around (1-2 teeth)?
Also, would you recommend I re-tension the belt from the motor side or the idler side?
You will want to re-tension the entire X belt assembly, working with the X motor mount and the X carriage.
I suggest that you first loosen the three screws that hold the X motor to the frame, then loosen the bolt that tensions the belt and the motor.
Then tighten the belt, one more tooth, in the X carriage and re-check the tension. You can then tighten the tension screw to the point that the belt is snug but is not so tight that it prevents free movement along the X axis.
Use pliers to hold the X motor shaft temporarily. The belt should be tightened just to the point that there is no discernible 'play' or 'slop' as you attempt to force the X carriage back and forth while holding the X motor shaft with pliers.
When it is tensioned properly, then tighten the three screws holding the motor.
Then double-check that the X carriage moves easily left and right and rotates the X motor as you do so with no 'play' in the belt.
TFM says to tension the belt so it feels like a bass guitar string, which is not very precise. There are also some tension gauges in the Prints section, but you will need a working printer to print these. You should be able to get things close enough without a tension gauge.
RE: Prusa X Belt Not Working
Thank you so much for the response! I will give this a try and let you know whether this fixes it or not 🙂
RE: Prusa X Belt Not Working
Here is a general update since @jsw's last post
My belt status shows that I am at 244. The belts are not as loose as they were before, but the belt test is still failing. I have also tried lubricating the x-rods (see the attached photo). Furthermore, there is some very noticeable skipping whenever I move the x-carriage towards the motor. I also forget to mention last time that I originally got the kit back in July 2021. I worked on it daily until August 2021 and then had to go to university. The printer remained untouched until late December 2021, and I have been working on it since. Would that length of time affect the printer in any way?
Currently my belt is two teeth down from the tightest the belt can be. 
If the printer was left for a long while it will have gathered dust, spiders and who knows what else so a thorough clean and relubricate is in order with especial attention to the smooth rods.
Cheerio,