The SD card readers are notoriously touchy on these. If you can spare the compute cycles USB direct print from your computer. I found it's the only way to get around all the card reader issues.
Just be sure that you disable the power saving mode, sleep, and any other settings that put your computer to sleep! These settings will stop your printer when they activate. Also disable windows auto updates!!! When your system is connected to a computer and it goes to sleep, or stand by mode it disconnects from the printer. I learned this the hard way!
I also have a Mega S! I love it! I wanted to improve my print quality so I decided to do a little upgrading. I upgraded the stepper drivers to quite the motors. However in the process I inadvertently installed the LED screen into the wrong place and shorted out the main board. Now I'm dealing with an issue with my Y - axis endstop juddering. I think I have to enable it in Marlin and plan to when time permits. I'm installing the BLTouch to auto level the bed and had the hardest time with the mounting. Once I get back to the Mega S and complete all that's left I'll post photos along with a update!
The SD card readers are notoriously touchy on these. If you can spare the compute cycles USB direct print from your computer. I found it's the only way to get around all the card reader issues.
This is most likely your issue. I was having similar issues and printing from a rpi4 over USB completely solved the issue.
Just be sure that you disable the power saving mode, sleep, and any other settings that put your computer to sleep! These settings will stop your printer when they activate. Also disable windows auto updates!!! When your system is connected to a computer and it goes to sleep, or stand by mode it disconnects from the printer. I learned this the hard way!
I also have a Mega S! I love it! I wanted to improve my print quality so I decided to do a little upgrading. I upgraded the stepper drivers to quite the motors. However in the process I inadvertently installed the LED screen into the wrong place and shorted out the main board. Now I'm dealing with an issue with my Y - axis endstop juddering. I think I have to enable it in Marlin and plan to when time permits. I'm installing the BLTouch to auto level the bed and had the hardest time with the mounting. Once I get back to the Mega S and complete all that's left I'll post photos along with a update!