So here we go the picture is a gif animation, 3 sec for every pic.
You can see the small spot circled in red.
I know it could be a lot of things, whether the stepper is doing uneven work, the carriage is loose, cheapskate,etc. I have done few check already, and I couldn't figure out for a while. You guys got any idea?
Spoiler:
http://www.mediafire.com/convkey/452e/t ... u241fg.jpg