Stepper vibrating with GRBL, works well with Merlin/RAMPS 1.4

I am trying to build small CNC based on GRBL. I've bought GRBL shield on ebay and wired everything. When I try to run stepper it vibrates a lot. I've set current on driver, and numbers of steps in configuration. I'am using 12V ATX power supply. You can hear it in following video:



First I thought it was motor problem, but then I've connected same motor to RAMPS 1.4 board with Marlin software. It uses same drivers (A4988). When I run it in this...

Stepper vibrating with GRBL, works well with Merlin/RAMPS 1.4