Ramps board gone wonky

First off let me say I am new to this kind of thing and bought a 10" I3V which I completed a couple days ago. It was easy and fun to build thanks to all the posts here and Colin's excellent videos. Right from the first test cube I got excellent results with both ABS and PLA, this thing rocks! After printing 5 objects over last few days I turned it on this afternoon and the X axis wouldn't move. I swapped connectors and determined it was the X axis on ramps board not the X stepper motor. Wanting to print something I just kept power cycling the printer and selecting home command on LCD. About the 4th cycle a loud high pitch tone started which lasted about 15 seconds then stopped. I think the sound was coming from ramps board. After that the X motor worked perfect and I have had two successful prints since. Have any of you experienced this with your ramps printer? I probably won't bother Colin with this unless it happens again, just wondering if this is something that happens occasionally. Thanks.

Follow up. Not working again today. Time to talk to Colin.

Yeah, I don't recall anyone reporting similar symptoms here. Have you tried swapping the stepper motor drivers around? Maybe the problem is on the stepper driver for the X motor.

Good idea, thanks! That worked. I actually swapped X and Y and they are both working again. I guess if I have further trouble with that particular driver again (now on Y) I will try bumping voltage up a bit. If X fails again I will know it's the board.