High pitched whining noise, no stepper movement

I have some standard A4988 Drivers in my Kingprint KFB 2.0 Smoothieware board on my delta printer.
For some reason, I'm just getting a high pitched whine noise when trying to move the motors.
Right now, 4.2v is being outputted from each driver (This is the minimum), and upon adjusting the current, the pitch just gets louder and turns into a static noise (similar to what you'd hear on a tv when you're not on the right channel).

Edit:
It is using all 3 jumpers for stepping modes.
Any advice?

Thanks,
Jack

Edited 2 time(s). Last edit at 01/28/2018 06:46PM by JackD.

The best way to adjust stepper current is with multimeter set on dc volts the negative probe connect to ground and the positive clipped to a small jeweller type screwdriver that when touched to adjustment pot gives a reading of 0.7 volts. Initially done without stepper then done with stepper then done while stepper is moving. This voltage may vary slightly if you are too high or too low you will have noise and no movement you need happy middle. You actually measure while turning. Note if current is too high too long an internal driver shutoff will occur get back to 0.7 let it cool down keep trying

Quote
Roger123D
The best way to adjust stepper current is with multimeter set on dc volts the negative probe connect to ground and the positive clipped to a small jeweller type screwdriver that when touched to adjustment pot gives a reading of 0.7 volts. Initially done without stepper then done with stepper then done while stepper is moving. This voltage may vary slightly if you are too high or too low you will have noise and no movement you need happy middle. You actually measure while turning. Note if current is too high too long an internal driver shutoff will occur get back to 0.7 let it cool down keep trying

^this ^

I had the this same issue when I moved to DRV8825 drivers. Adjusted the trimpots as Roger says and the problem was fixed. I actually came to know just where that sweet spot was by the sound my motors were making...turn it back until the squealing goes away. It's fairly simple to do.