I’m not sure it’s the motor. Is there friction anywhere? Is the motor geared? In other words, can you manually spin the motor? I would recommend taking the motor off of whatever mechanism it’s powering and seeing if the motor is still broken in the one direction.
Just to clarify – the motor works perfectly in one direction (you can vary the speed and stop it using the joystick), but won’t spin in the other direction? Do other motors plugged into the same port run in both directions?
What do you mean exactly by default code? Do you mean the master firmware or do you really mean the “default” code? (In other words, you have not written any code of your own, you are using the VEX supplied program )
Try using the “online” dialog box in EasyC, can you control the motor with this?
Best way to check a motor is using the 9V backup battery, just connect red-red and black-black and check motor spins, reverse and check the other way, don’t leave connected for very long.
It does sound like port 1 is broken, nothing you can do about that except send back to VEX.
How are you using the Y-cable? The Y-cable plugs into a 3-wire port (port 2 through 9), two MC29’s (motor controller 29) are plugged into the Y-cable and a motor into each one. Make sure the polarity of the wiring is correct, match black with black etc. If the MC29 is plugged into the y-cable with the polarity reversed it will not work. You cannot use a 2-wire motor directly with a Y-cable, you cannot use a Y-cable on the output of an MC29, ie. two motors on one motor controller is not allowed.
The same as having two motors powered separately. You still need to consider the total power on one cortex circuit (the cortex has two thermal fuses, one for motor ports 1 through 5 and another for ports 6 through 10) in the same way as you would if not using a Y cable.