By default your 107 is getting 5+, your JP3 should be connected with trace to +5. With US console, you need to cut that trace and also JP3 trace I guess. Because theres got to be some difference in genesis 2 model than pal mega drive 2 model. Also lift the 107.
When done these actions for ON-OFF-ON switch mod, Your genny should still run as US console if this is doable. Other wayyou need to have ON-ON-ON switch and solder all the way mmmonkey explains.

