Y skipping (6 replies)

so tonight while printing my Y axis started grinding/skipping after about an hour into a print. The last time this happened was when i first build the printer and i was told to up the current of the trimmer by 1/8 turn and it never did it again until today. And i have printed for many 6+ hour days with no issues. I have a 40mm fan blowing across the ramps and the drivers have heat sinks on them. Is my driver bad? does it need to be turned up a bit more? oh and belt is ok not too tight not too lose

Any advice would be appreciated