Hi all, A few days ago I finished building my new printer - a custom design printer with lead screws on all axis kind of like the Trinus. I designed it specifically to use an E3D Titan and V6.1. It worked perfectly for the first couple of days (see the insane 0.1mm Yoda print i got off of it). This morning I was printing a few replacement parts that included quite a lot of retraction. Default retraction settings in new Cura were 6.5mm at 25mm/s, which I thought were a bit too high for this printer design, so i reduced to 2mm at 18mm/s and added 0.4mm z-hop. The print stuffed up, and since then I cant get my titan to extrude. When steppers are disabled, I can manually turn the gear to extrude the filament no worries - so the Titan is fine, and the V6.1 is not blocked at all. Tension on the filament is also fine. When I extrude using pronterface or the dial on my LCD, it clicks as if the stepper is wired incorrectly. Quickly jerking backwards and forwards. Its using one of these stepper motors. Running on DRV8825's on an AZSMZ mini with latest smoothieware. I've tried replacing the stepper driver with a brand new DRV8825, no result. I've checked the current is set correctly (used the maths from here to calculate this for a 1.0A stepper). What is left for me to do besides replace my stepper motor? Is there a way to test if it's dead without having another spare one to put in its place?