What is Pronterface and how do I get it?
Pronterface is a free, downloadable program that allows you to check the functionality of different parts of the printer. To visit Pronterface's download page, click here or go to www.pronterface.com, click download on the top menu, then click Windows and OSX Binaries. Select the latest version for your operating system.
How do I connect my printer?
Turn your printer on and connect to your computer using the USB cable. In Pronterface, select the correct connection for Port (green in photo below) and change the number following the @ to 250000 (blue in photo below). Then hit connect.
How do I check for XY errors or endstop functionality?
Make sure your print head is in the middle of the printer away from the endstops, and that you have the bed raised up so that the Z stop is not triggered. You then type in the command line M119 and hit send (blue in the photo below).
It should tell you that the X, Y, and Z endstops are open. Then, move the printhead to the back left corner by hand, triggering both endstops, and push the bed to the bottom of the printer, and type of the command line again and see if it says that your endstops are triggered.
If the endstops are reporting accurately, you can move on to the next step. If they're not reporting accurately, then one of your endstops is bad.
The lefthand side of Pronterface has a square/circle section with arrows indicating X and Y movement. Try to move the printhead using the arrows in either the X direction or the Y direction. If it successful in one direction, try the other direction.
If the printer fails in one direction or the other and reads off the XY error, you'll want to remove the electronics cover below your printer and switch the X motor cable and Y motor cable and then repeat the process again to determine whether the failure was caused by the board, or the motor. Please follow the instructions for removing the electronics board cover here.