Just for reference the color DMD draws 570ma from the +12v unregulated source and  3.4ma  from the +5 volt source

If the LCD for the under the play field is drawing the same amount then between the 2 of them you may have just over an extra amp on the 12v supply which only has a 3 amp fuse so you may be exceeding the capabilities of the un regulated 12 volt supply

That's just one possible reason why the fuse is blowing