I have an original Makerbot Replicator Dual which has been my workhorse for years. Firmware was upgraded to Sailfish, extruders rebuilt, and suggested mods made to the Mightyboard. It's connected via OctoPi as most people do now. It's been flawless for several years, just regular cleaning & maintenance.
Lately the printer has not been homing on the X axis. Whether I use the "Home Axes" function on the printer or a G-Code "G28 X Y Z", the Y & Z axes home but the X remains stationary. I can move it along the X-axis using the jog functions on the printer or via Octoprint, so X isn't dead. It appears it's only in the +X direction that it's not moving, e.g. from -40,40 a G1 X40,40 will not move the extruder.
Any ideas where to start looking? Stepper motor? Driver module? New printer?