Mini 1 Z-Axis "Chattering" - HELP!!

My trusty old Mini 1 has developed a problem. The Z-Axis motors have become very loud and are “Chattering”. Their movement is erratic and now all movement has stopped. I just re-flashed the firmware to try and fix the problem but no luck. Any ideas?
Since the factory isn’t up yet with the new owners I thought I’d give you all a try…

Check your wires and reseat your connections, just in case you have something going on there.

The most common cause of this condition is a failed Rambo board motor driver, unfortunately. Since the Z wiring harness doesn’t move, a broken wire isn’t very likely.

Thanks for the help.
I did check the wiring and reset the connectors on the board to no avail.
I did notice that the Z-axis motors moved slightly in BOTH directions with a single command to move up 5mm. That in essence must mean that the board is faulty.
I’ve ordered a new board hoping to be back printing soon…

99.9% it is the board. I have seen this waaaaay too many times.