Y axis has gone bad all of a sudden

[bkmartin]

When I print a test cube now, my y-axis seems to have problems. Any ideas on what could cause this? My belts are tight and I tried increasing the stepper voltage and I get the same result. The x-axis appears ok

View from side (of printer of a test cube). The irregular edge on the right would be at the front of the printer. Rear is similar


View from front of printer [edges are uniform]



Last week, the same filament and same gcode printed fine.