If both RA and Dec motors produce a yellow light then the mount is probably ok. It indicates that there's a loose connection between the controller and the mount gearboxes, most likely in the RA cable. Remove the cover on the cable and look for a loose wire on the pins.
Just to clarify, you are asking me to check the Y-cable, Ra side and see for loose wires or pins? This for both the old one and the new one AP shipped to me last week?
As far as gears rotating 180 degrees, that statement is puzzling. The gearbox has a number of gears and they all rotate at different rates, so when you say gears, which one are you referring to/ The little gear on the end of the motor shaft, the white gear, the large center gear, or the final gear on the worm shaft?
Maybe it was more, a couple of rotations. It was hard to tell as they did rotate very fast for a fraction of a second.
Secondly, how fast did the gear rotate? Very quickly or slowly at the sidereal rate?