The upside down ACC board swaps the X and Z parts of the board. The Y is still the same. Check the voltage at the fuse. You may have an open leg on the bridge rectifier. Do you have plug in fuses or screw in? The screw in have a tendency to develop a high resistance and cause problems. Have you checked the current at the fuse? Bad ACC or bridge rectifier. Chips or screws or washers falling down between the diodes on the board beneath the SMD or onto the terminal strip to the motors will also cause a problems such as yours.
Start with the above.
George
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)