Normally the A4988 have some protection which should help to avoid killing them... but anyhow:
The easiest way to check if something is broken... change one hardware piece at a time and test again. The cheapest (and most likely damaged) part is the stepper driver. But before buying (and paying for "lessons learned") a new driver you should check the output current (by checking the contol voltage on the stepper driver).
Details for that are explained here:
[reprap.org]
So all the best and fingers crossed for the damage inspection!
Lutjanus
The easiest way to check if something is broken... change one hardware piece at a time and test again. The cheapest (and most likely damaged) part is the stepper driver. But before buying (and paying for "lessons learned") a new driver you should check the output current (by checking the contol voltage on the stepper driver).
Details for that are explained here:
[reprap.org]
So all the best and fingers crossed for the damage inspection!
Lutjanus