Geeetech

power supply and both side of fuse are 12v what next

Hi

I have a prusa i3 pro B printer the control board is not working the power led is on I tested has 12v for both output the lcd display is blank and the printer is not showing up in my pc
How I test the board to see if it is defective
Please can someone help me I'm new to 3d printing
Thanks in ...