I have been having a problem with my printer stopping in the middle of a print. The message I am getting with pronterface is that it has lost its connection. The heatbed & Hotend still stay at the same temperature, the printer just stops moving. I thought it might be a heat related problem with the electronics, so I had a small fan blowing on the arduino & it got thru a 40 minute print, but then lost its connection soon after the print ended. Since I have a spare Arduino mega on my CNC machine, thought I would substitute the drivers on that board to see if that fixed it, but they are DRV8825 & ones on my i3v are A4988. This web page says they are interchangeable http://reprap.org/wiki/A4988_vs_DRV8...tepper_drivers but it seems like I will need to adjust something in the firmware for them. I only have 3 DRV8825 drivers, so I am planning to change the X, Y & Z, but leave the A4988 for the extruder. I had this same problem with octoprint. I also swapped a usb cable & reseated all the connections. Anyway, does anyone know the settings I should change Marlin in the Configuration.h file or have a different suggestion? Looks like it might be this value that needs to change:

#define DEFAULT_AXIS_STEPS_PER_UNIT {80,80,4000,841}