Hmm... what board version is it? (It will be printed on the board as VAx where x is a number from 1 to 6.)
If it's VA3 or earlier, it probably doesn't have the 50/60Hz jumpers (JP3 and JP4), as the PAL machines weren't available at that time (1989 ish). You should still be able to do the 50/60 mod though, (possibly by cutting a trace or lifting a chip pin), but it's impossible to say without seeing the board.
Well my genesis model 1 i think is a later model as it does not have the port in the back for the modem or the high 16bit graphics system label on the top.By bottom do you mean the the other side of the pcb? Also i did check carefully and still can't find any more jumpers.And i'm sure it is one of the model 1 gen that prevents unautorized games to play. :woah:
On a VA7 Genesis motherboard, the JP3 and JP4 switches are on the upper left side about 1 to 1 and 1/2 inches below the RF output box. A couple of capacitors or transistors are bent to cover them up, but they are noticeable if you view them from an angle.