You don't need to trim the shell if you haven't purchased the HDMl version
remove the screen
After remove the components
Connect the T10 to T11
Connect the FPC cable.
Connect BUT1 to c30,BUT2 to c29,BUT3 to C28.Connect R23 to T10.
Replace R34 with 0 Ohm/bridge.
Connect the R to M41, L to M42.
Connect the BK, SMS, 5V as show below.
Place the SEGA motherboard into the shell and connect the flex cable.