@dc42 I pulled out the SD card and made sure everything is unplugged.
The only area that got warm is under the board where the motor microprocessors are. It got a little warm where the driver microprocessors are, but no where else.
When plug the board into the computer only the 5.5v light comes on, but the 5.5v light does not come on when plugged into the mains power.
Could there be something going on with the 5.5v rail as well as the 3.3v rail?
Thank you
Lachlan